 

















                     Compaq_C++_Version_6.5________________________
                     Release Notes for Compaq Tru64 UNIX


                     April, 2002

                     This document contains information about new and
                     changed features in this version of Compaq C++ for
                     Tru64 UNIX.





















                     Compaq Computer Corporation
                     Houston, Texas

 






           __________________________________________________________

            2002 Compaq Information Technologies Group, L.P.

           COMPAQ, the Compaq logo, Alpha, Ladebug, and Tru64 are
           trademarks of Compaq Information Technologies Group,
           L. P. in the U.S. and/or other countries. Microsoft and
           Visual C++ are trademarks of Microsoft Corporation in the
           U.S. and/or other countries. UNIX is a trademark of The
           Open Group in the U.S. and/or other countries. All other
           product names mentioned herein may be trademarks of their
           respective companies.

           Portions of the ANSI C++ Standard Library have been
           implemented using source licensed from and copyrighted
           by Rogue Wave Software, Inc.

           Information pertaining to the C++ Standard Library has
           been edited and reprinted with permission of Rogue Wave
           Software, Inc. All rights reserved.

           Portions copyright 1994-2002 Rogue Wave Software, Inc.

           Confidential computer software. Valid license from Compaq
           required for possession, use or copying. Consistent with
           FAR 12.211 and 12.212, Commercial Computer Software,
           Computer Software Documentation, and Technical Data for
           Commercial Items are licensed to the U.S. Government under
           vendor's standard commercial license.

           Compaq shall not be liable for technical or editorial
           errors or omissions contained herein. The information
           is provided "as is" without warranty of any kind and is
           subject to change without notice. The warranties for
           Compaq products are set forth in the express limited
           warranty statements accompanying such products. Nothing
           herein should be construed as constituting an additional
           warranty.

           This document was prepared using DECdocument, Version
           3.3-1n.

 













   ________________________________________________________________

                                                           Contents


         1     Introduction.................................      1
         2     Important Compatibility Information..........      1
         2.1       Run-Time and Standard Library
                   Differences..............................      2
         2.2       Compiler Differences.....................      2
         2.3       Difference between Compaq C++ and the C++
                   International Standard...................      3
         2.4       Retirement of CFRONT language dialect....      4
         2.5       Retirement of -oldcxx compiler support...      4
         3     Release Notes for the C++ Compiler...........      4
         3.1       Enhancements, Changes, and Problems
                   Corrected in V6.5-020....................      4
         3.2       Enhancements, Changes, and Problems
                   Corrected in Version 6.5.................      4
         3.3       Enhancements, Changes, and Problems
                   Corrected in V6.3-018....................      5
         3.4       Enhancements, Changes, and Problems
                   Corrected in V6.3-014....................      5
         3.5       Enhancements, Changes, and Problems
                   Corrected in V6.3-013....................      5
         3.6       Enhancements, Changes, and Problems
                   Corrected in V6.3-012....................      5
         3.7       Enhancements, Changes, and Problems
                   Corrected in V6.3-011....................      6
         3.8       Enhancements, Changes, and Problems
                   Corrected in V6.3-010....................      6
         3.9       Enhancements, Changes, and Problems
                   Corrected in V6.3-009....................      7
         3.10      Enhancements, Changes, and Problems
                   Corrected in V6.3-008....................      7
         3.11      Enhancements, Changes, and Problems
                   Corrected in V6.3-007....................      7


                                                                iii

 






           3.12      Enhancements, Changes, and Problems
                     Corrected in V6.3-006....................      7
           3.13      Enhancements, Changes, and Problems
                     Corrected in V6.3-005....................      8
           3.14      Enhancements, Changes, and Problems
                     Corrected in V6.3-003....................      8
           3.15      Enhancements, Changes, and Problems
                     Corrected in Version 6.3.................      8
           3.16      Restrictions in Version 6.5..............     12
           3.17      Restrictions in Version 6.3..............     13
           3.18      Enhancements, Changes, and Problems
                     Corrected in Version 6.2-040.............     15
           3.19      Enhancements, Changes, and Problems
                     Corrected in Version 6.2-037.............     16
           3.20      Enhancements and Changes in Version
                     6.2......................................     18
           3.21      Problems Corrected in Version 6.2........     19
           3.22      Restrictions in Version 6.2..............     22
           3.23      Problems Corrected in Version 6.1-029....     26
           3.24      Problems Corrected in Version 6.1........     27
           3.25      Enhancements and Changes in Version
                     6.0......................................     30
           4     Release Notes for the C++ Standard Library...     31
           4.1       Enhancements, Changes, and Problems
                     Corrected in 6.5-020.....................     31
           4.2       Enhancements and Changes, and Problems
                     Corrected in Version 6.5.................     32
           4.3       Enhancements, Changes, and Problems
                     Corrected in Version 6.3.................     32
           4.4       Restrictions in Version 6.3..............     34
           4.5       Enhancements, Changes, and Problems
                     Corrected in Version 6.2-037.............     34
           4.6       Enhancements and Changes in Version
                     6.2......................................     35
           4.7       Problems Corrected in Version 6.2........     36
           4.8       Restrictions in Version 6.2..............     41
           4.9       Enhancements and Changes in Version
                     6.1-029..................................     48
           4.10      Problems Corrected in Version 6.1-029....     49
           4.11      Enhancements and Changes in Version
                     6.1......................................     51
           4.12      Problems Corrected in Version 6.1........     56



     iv

 






        1 Introduction

              This document contains the release notes for Compaq C++
              Version 6.3 for Compaq Tru64 UNIX.

              This kit installs two compilers:

              o  The cxx command invokes the Version 6.5 compiler.

              o  The cxx -oldcxx command invokes the 5.7 compiler. The
                 version is V5.7-002. This compiler will not be included
                 in future kits.

                ________________________Note  ________________________

                The Version 5.7 compiler's lack of support for 128-
                bit long doubles can cause crashes on Compaq Tru64
                UNIX Version 5.0 or later.

                _____________________________________________________

              HTML files are provided for the release notes and some of
              the product manuals for use with a web browser. You can
              install these files by selecting the subset Compaq C++
              HTML documentation.

              To view this documentation, point your browser to

                   /usr/share/doclib/cplusplus/index.htm.

        2 Important Compatibility Information

              Compaq strives to maintain a high degree of compatibility
              between successive versions of the compiler and its run-
              time environment. Because, however, each new version
              includes enhancements and changes, you should be aware
              of the following whenever you upgrade:

              o  Differences between Run-Time and Standard Library
                 versions

              o  Differences between compiler versions

              o  Difference between Compaq C++ and the C++ International
                 Standard

              o  Retirement of cfront language dialect

              o  Retirement of -oldcxx compiler support

                                                                       1

 






           The next sections discuss these differences.

     2.1 Run-Time and Standard Library Differences

           Applications must use a version of the C++ Run-Time
           library (libcxx) that provides all the functions they
           require. If an application is linked shared, and the
           correct library version is not installed, "undefined
           symbol" error messages appear at run time. Changes in
           the Run-Time Library occurred in Versions 6.0, 6.2, and
           6.3.

           For information about redistributing the C++ Run-Time
           Library, see Deploying Your Application in Using Compaq
           C++ for Tru64 UNIX and Linux Alpha.

           Any code that references the C++ Standard Library (any of
           the STL containers or algorithms, standard iostreams or
           locales) may need to be recompiled and relinked because
           there is no guarantee that the C++ Standard Library
           shipped with a given version of the C++ compiler will
           be compatible with the C++ Standard Library shipped with
           previous versions. This restriction does not apply to code
           that references the pre-standard class library, because
           the stability of that library's interface guarantees link
           compatibility in future releases.

     2.2 Compiler Differences

           Starting with Version 6.0, the Compaq C++ compiler
           differs significantly from previous versions. There are
           several major differences that you should be aware of
           before using a Version 6.n compiler for the first time.
           These differences are summarized here. For more detailed
           information, see Porting to Compaq C++ in Using Compaq C++
           for Tru64 UNIX and Linux Alpha.

           o  Language differences

              The compiler implements most of the C++ International
              Standard, which differs significantly from the language
              specified in the ARM (The Annotated C++ Reference
              Manual, 1991, by Ellis and Stroustrup) with some ANSI
              C++ extensions. When switching from a Version 5.n
              compiler, you might need to modify your source files,
              especially if you use the default language mode. In

     2

 






                 addition, language changes can affect the run-time
                 behavior of your programs. If you want to compile
                 Version 5.n source code with minimal source changes,
                 specify the -std arm option. See Porting to Compaq C++
                 in Using Compaq C++ for Tru64 UNIX and Linux Alpha.

                 If Version 6.n requires excessive changes to your
                 applications even when you use the -std arm option,
                 or if you encounter problems using the Version 6.n
                 compiler, you can compile using the cxx -oldcxx
                 command. If you discover a compatiblity problem that is
                 not documented, please file a PTR or SPR.

              o  Diagnostic differences

                 The Version 6.n compiler does more error checking than
                 Version 5.7 and generates more diagnostics. If you want
                 the number of diagnostics issued by the Version 6.n
                 compiler to be similar to Version 5.7, compile with
                 the -msg_quiet option. For details, see Message Control
                 Options in Using Compaq C++ for Tru64 UNIX and Linux
                 Alpha.

              o  Implementation differences

                 The automatic template instantiation model has
                 been redesigned for the current version. Although
                 code compiled with Version 5.n and 6.n compilers
                 can be combined, you must complete the Version 5.n
                 instantiation process with a Version 5.n (or specify
                 the -oldcxx option) before linking with code compiled
                 with Version 6.n. See Using Templates in Using Compaq
                 C++ for Tru64 UNIX and Linux Alpha.

        2.3 Difference between Compaq C++ and the C++ International
            Standard

              The export keyword for templates (Standard 14, paragraph
              6; Stroustrup 9.2.3) is not supported in Version 6.3 but
              will be supported in a future version:





                                                                       3

 






     2.4 Retirement of CFRONT language dialect

           The CFRONT dialect was provided for migrating code from
           the CFRONT compilers to the Compaq C++ compiler. Because
           it has been over five years since the last CFRONT compiler
           was released, we are retiring this dialect: it will be
           removed from the next release of the compiler. If you
           depend on the CFRONT dialect, please send email to the C++
           team at  compaq_cxx@compaq.com.

     2.5 Retirement of -oldcxx compiler support

           The -oldcxx compiler was provided for migrating code from
           the V5.n to the more ISO/ANSI compliant V6.n compilers.
           Since it has been over three and a half years since V6.0
           was released, we are retiring this compiler support: it
           will be removed from the next release of the compiler. If
           you depend on the -oldcxx compiler, please send email to
           the C++ team at  compaq_cxx@compaq.com.

     3 Release Notes for the C++ Compiler

           The following sections describe enhancements, changes,
           problems corrected, and restrictions for the C++
           compiler.

     3.1 Enhancements, Changes, and Problems Corrected in V6.5-020

           o  Improved compiler optimization resulted in reduced
              abstraction penalty in Stepanov benchmark.

     3.2 Enhancements, Changes, and Problems Corrected in Version
         6.5

           Enhancements, changes, and problems corrected are as
           follows:

           o  Improved conformance to the C++ International Standard

           o  Improved code optimization

           o  Retirement of CFRONT dialect announced

           o  Retirement of -oldcxx compiler announced

     4

 






              o  The compiler supports C/C++ OpenMP Version 1.0. By
                 default, the compiler ignores all C++ OpenMP directives
                 unless you specify the -omp option. For example:

                 cxx -omp omp_program.cxx

        3.3 Enhancements, Changes, and Problems Corrected in V6.3-018

              o  Compiler and libraries are built with a new C compiler
                 to improve performance.

              o  The iversion string for libcxx.so has been updated
                 to work around a bug in the loader in Tru64 V5.1 that
                 prevented the library from being loaded.(8638) This
                 is the same fix made in -011, the fix was missing from
                 -012, -013, and -014.

        3.4 Enhancements, Changes, and Problems Corrected in V6.3-014

              o  Compiler crash processing va_list eliminated. (8803)

              o  Problem with dynamic cast of standard library types
                 corrected. (8828)

        3.5 Enhancements, Changes, and Problems Corrected in V6.3-013

              o  Runtime crash in exit when program is compiled "-g" and
                 atexit is used has been eliminated. (8800)

              o  Runtime hang when two tied streams share the same
                 streambuf object has been eliminated. (cxxl1641)

              o  Runtime problem with memcpy family of intrinsics has
                 been corrected. (8824)

        3.6 Enhancements, Changes, and Problems Corrected in V6.3-012

              o  In previous releases, the compiler treated string
                 literals as pointers to const char (const char *) in
                 -std strict_ansi and -std strict_ansi_errors modes,
                 but as pointers to char (char *) in all other -std
                 modes. This could lead to incompatibilities between
                 the object generated under the former -std modes and
                 the latter ones. The -std option no longer controls how
                 string literals are treated. Instead, the -model option
                 controls this behavior. In the arm object model (-model

                                                                       5

 






              arm, the default on Tru64 Unix), string literals are
              treated as char *. In the ansi object model (-model
              ansi, the default on Alpha Linux), string literals are
              treated as const char *. (Objects generated using the
              -model arm option are incompatible with the objects
              generated using the -model ansi option. The -model arm
              option is unavailable on Alpha Linux.) (8659)

           o  The compiler once again correctly recognizes intrinsics
              with variable number of arguments. (4850)

           o  Runtime crash when using iostream with long double on
              V5.0 Tru64 has been eliminated. (cxxl1623)

           o  Destructor is no long envoked for uncreated object in
              "?" expression. (8736)

           o  Destructor is no long skipped on exception for object
              with initializer. (8772)

           o  Code optimization generating incorrect code has been
              correct. (8762)

     3.7 Enhancements, Changes, and Problems Corrected in V6.3-011

           o  A multithread safety problem which can lead to
              corruption or deadlocking when using the C++ standard
              library iostreams and locales has been fixed.(L1625)

           o  The iversion string for libcxx.so has been updated
              to work around a bug in the loader in Tru64 V5.1 that
              prevented the library from being loaded.(8638)

           o  The compiler no longer aborts when using pointers to
              members.(8632)

     3.8 Enhancements, Changes, and Problems Corrected in V6.3-010

           o  The compiler no long aborts when processing a class
              that imports a set of overloaded delete operators from
              a base class with a using-declaration or an access
              declaration. (8611)



     6

 






        3.9 Enhancements, Changes, and Problems Corrected in V6.3-009


              o  The compiler no longer generates __init_sti names
                 incorrectly which was resulting in duplicate symbols.
                 (8568)

              o  The demangler no long crashes on names beginning with
                 __INTER. (8553)

              o  The archive version of libdemangle has been added to
                 the kit. (8553)

              o  The compiler no longer crashes when -xref is used and
                 duplicate templates are encountered. (8501)

              o  The compiler no longer encounters a catastrophic error
                 on a conditional operator. (8481)

              o  The compiler no longer encounters a catastrophic error
                 on a virtual base class. (8477)

              o  A multithread safety problem which can lead to
                 corruption or deadlocking when using the C++ standard
                 library iostreams and locales has been fixed.(L1561)

        3.10 Enhancements, Changes, and Problems Corrected in V6.3-008

              o  The compiler no long generates identifier undefined
                 warnings in <math.h> when compiling -fast with Unix
                 standard macros.

        3.11 Enhancements, Changes, and Problems Corrected in V6.3-007

              o  The GEM backend was upgraded.

              o  Documentation updated to reflect 6.3A release.

        3.12 Enhancements, Changes, and Problems Corrected in V6.3-006

              o  Components of the "-oldcxx" compiler are now in the
                 appropriate subset.

              o  Fixed arch EV68 support.

                                                                       7

 






     3.13 Enhancements, Changes, and Problems Corrected in V6.3-005


           o  The compiler no longer generates an error when
              compiling pthreads.h with "-std strict_ansi."

           o  The GEM backend was upgraded.

     3.14 Enhancements, Changes, and Problems Corrected in V6.3-003

           o  The compiler no longer generates a compiler memory
              access violation for a local function declaration
              inside a member function with the same name as a
              virtual and a non-virtual function in the function's
              base class.

           o  The compiler no longer generates a memory access
              violation when it sees a reference to a <cname>
              structure in a function prototype before the <cname>
              structure is declared.

     3.15 Enhancements, Changes, and Problems Corrected in
          Version 6.3

           Enhancements, changes, and problems corrected are as
           follows:

           o  This version of the C++ compiler implements C++ headers
              for C Library Facilities. The <cname> headers avoid
              pollution of the global namespace by defining all C
              names only in namespace std. (See Stroustrup, 9.2.2
              and 16.1.2.)

              The <cname> headers are located in the directory
              /usr/include/cxx_cname.

              If you include a <cname> header and use the -pure_cname
              option, all C functions and types found in that header
              file are declared only in namespace std, as specifed by
              the C++ International Standard.

              Specifying the -nopure_cname option causes <cname>
              headers to be handled as if the corresponding <name.h>
              version had been included. That is, names are available
              both in namespace std and global scope.

     8

 






                 The default is -pure_cname when compiling with -std
                 strict_ansi and -std strict_ansi_errors. The default is
                 -nopure_cname when compiling with -std ansi, -std arm,
                 -std gnu, -std ms, and -std cfront.

                 The compiler search order for include files has been
                 changed from

                    /usr/include/cxx
                    /usr/include

                 to

                    /usr/include/cxx
                    /usr/include/cxx_cname
                    /usr/include

                 Including <name.h> after including the corresponding
                 <cname> header brings all names declared in that
                 <cname> header into global namespace with "using
                 std::name" declarations.

                 New Header Files and protect_headers_setup

                 The addition of <cname> headers adds several new files
                 and the new subdirectory /usr/include/cxx_cname. If
                 you are using protect_headers_setup on your system, you
                 might need to rerun it after installing or upgrading
                 to the Compaq C++ Version 6.3 compiler. For more
                 information, see the protect_headers_setup(8) reference
                 page or Protecting System Header Files in Using Compaq
                 C++ for Tru64 UNIX and Linux Alpha.

                 Backward Compatibility

                 In -pure_cname mode, <cwchar> does not include
                 <cstdio>. Therefore, printf() is not declared unless
                 <cstdio> is included.

                 For example, the vfwprintf function, declared in
                 <cwchar>, requires that <cstdarg> and <cstdio> be
                 included:

                 int vfwprintf(FILE *, const wchar_t *, va_list);

                 New overloaded function signatures have been added to
                 several <cname> headers (see Standard 21.4, 25.4,
                 and 26.5). These overloaded signatures have been
                 made available when including the <cname> header in
                 -pure_cname mode. If the __CNAME_OVERLOADS macro is

                                                                       9

 






              defined, the new signatures are available in both -
              pure_cname and -nopure_cname modes. On some operating
              system platforms, defining the __CNAME_OVERLOADS macro
              in -nopure_cname mode in combination with other macros
              and options (for example, -ms, -D_XOPEN_SOURCE) can
              cause compile errors.

              cmath (Standard 26.5) now provides float and long
              double overloaded signatures for math functions in
              -pure_cname mode, or in -nopure_cname mode with the
              __CNAME_OVERLOADS macro defined. On some operating
              system platforms, defining the __CNAME_OVERLOADS macro
              in -nopure_cname mode in combination with other macros
              and options (for example, -ms, -D_XOPEN_SOURCE) can
              cause compile errors.

              These added signatures could cause type ambiguity
              problems or different runtime behaviour in existing
              code. Consider theses examples:

              o  sin(1) is now ambiguous because overloads are
                 provided for float, double, and long double. A user
                 sees the following differences, because the argument
                 of sin(1) is assumed to be of type int:

                     cout << "sin(1) = " << sin(1) << endl;  // generates an error

                     cxx: Error: t.cxx, line 15: more than one instance of overloaded function
                              "sin" matches the argument list:
                                function "std::sin(long double)"
                                function "std::sin(float)"
                                function "std::sin(double) C"
                                argument types are: (int)
                              cout << "sin(1) = " << sin(1) << endl;
                              -----------------------^

              o  The type of the argument to an overloaded math
                 function determines the type of its return value
                 and associated precision. Calls to math functions
                 using float or long double arguments may return
                 less precise or more precise values than previously.
                 Compare the following:

                 o  Previous compiler release:

     10

 






                       long double  ldout = sin(1.0);
                       ldout = 0.84147098480789650000

                    o  Current compiler release:

                       long double  ldout = sin(1.0);  // type int argument - ambiguous

                       long double  ldout = sin(1.0l); // type long double argument
                       ldout = 0.84147098480789650000

                       long double  ldout = sin(1.0f);  // type float argument
                       ldout = 0.84147095680236816000

                 Signatures have been added in cstring, cwchar, and
                 cstdlib header files for the following functions:

                    cstring: (Standard 21.4) strchr, strpbrk, strrchr,
                    strstr, memchr
                    cwchar: (Standard 21.4) wcschr,wcspbrk, wc-
                    srchr,wcsstr, wmemchr
                    cstdlib: (Standard 25.4) bsearch, qsort, (26.5)
                    abs, div

                 The added signatures could cause problems in existing
                 code. For example, because char* strchr(const char*,
                 int) now has overloads const char* strchr(const char*,
                 int) and char* strchr(char*, int), the following code
                 does not work:

                       #include <cstring>
                       void f(char*) {;}
                       int main() {
                          f(strchr("abc",1)); // strchr returns a const char*
                          return 0;
                       }

              o  The -t option has two new variants, -ti (include C++
                 header files) and -tj (include cname header files).

                 For a complete description of the -t option, see the
                 cxx(1) reference page.

              o  In strict_ansi mode, the name of a class is now entered
                 as a member of itself, as required by clause 9 (para 2)
                 of the Standard; this behavior is implemented more or
                 less as an implicitly declared member typedef and might
                 cause some existing programs to fail. For example:

                                                                      11

 






              namespace std {
                   class iterator {};
              }

              struct tree
              {
                  struct iterator {};
                  struct nested : public std::iterator
                  {
                    // Compaq C++ 6.2 and below thinks this is tree::iterator
                    // Compaq C++ ?? in strict_ansi mode thinks this is std::iterator
                    nested(const iterator&);
                  };
              };

              [6613]

           o  The error "incompatible parameter", issued when there
              is a difference in sign between pointers, has been made
              discretionary. As a result you can now reduce/increase
              the severity of this message or enable/disable it using
              its error tag incompatibleprm or its error number. The
              same can also be done by enclosing the offending code
              in #pragma. For Example, the error message for the
              following program can now be controlled.

              void f(unsigned int *i) {
              }
              void main() {
                f((int *)0x05);
              }

              In addition, specifying -std gnu reduces the message
              severity to warning.

     3.16 Restrictions in Version 6.5

           The following restriction applies for the Version 6.5
           release:

           o  When the mbrtowc() function on RedHat V7.0 is passed
              a null character, it fails to write zero (L'0') into
              the output wide character. This behavior can cause the
              codecvt_byname<wchar_t,char,mbstate_t>::in() function
              to generate an incorrect sequence of wide characters if

     12

 






                 an input sequence of (multibyte) characters contains a
                 null character.

        3.17 Restrictions in Version 6.3

              The following restrictions apply for the Version 6.3
              release:

              o  In Version 5.n, if you allocate an array of objects
                 of a class type with a constructor but without a
                 destructor using new[n], you will be unable to
                 deallocate this object using delete[] in a module
                 compiled with Version 6.n because the hidden count was
                 not stored during the allocation. [7232]

              o  Because the task library is being retired, it is no
                 longer a shared object. You must therefore specify -
                 threads -lcmalib on the cxx command line in addition to
                 -ltask for the link. [7976]

              o  A template mangling problem can occur if you use class
                 template partial specializations with non-type template
                 arguments in the compiler's model arm mode.

                 For example, the following program produces a
                 compilation error:

                 template <int i, int j> struct C {};
                 template <int i, int j, class S> struct D {};

                 template<int Dim1, int Dim2, int Dim3>
                 struct D<Dim1, Dim2, C<Dim1, Dim3> >
                 {
                   void foo();
                 };

                 template<int Dim1, int Dim2, int Dim3>
                 struct D<Dim2, Dim1, C<Dim1, Dim3> >
                 {
                   void foo();
                 };




                                                                      13

 






              int main() {
                  D< 1, 2, C<2, 1> > d;
                  d.foo();
                  D< 2, 1, C<2, 1> > d2;
                  d2.foo();
                  return 0;
              }

              The problem occurs because the two instantiations of
              foo() are incorrectly mangled identically. As shown in
              the example, this happens when the template parameter
              list is instantiated with the same arguments in the
              same order, but the template argument list is actually
              different.

              If the calls to D<...>::foo() were made from two
              different source files, the compiler would not give
              an error; instead it would incorrectly call the same
              instantiation for both calls.

              This problem cannot be corrected without breaking
              link compatibility with objects produced from the
              previous releases. The name is mangled correctly in
              the compiler's model ansi mode. For more details on the
              model ansi compiler option, see the description of the
              -model [ansi | arm] option in the cxx.1 reference page.
              [8012]

           o  A problem in libexc on Tru64 UNIX before Version 4.0E
              generates an error message when an exception is thrown
              from a constructor that will be called by a static
              initialization, as in the following example. The
              error message appears after the example. There is no
              workaround for the problem.

              #include <stdio.h>
              #include <exception>
              #include <stdlib.h>

              void term_handler()
              {
                   printf("in terminate handler\n");
                   abort();
              }

     14

 






                 class C {
                   public:
                      C() {
                            std::set_terminate(&term_handler);
                            throw 5;
                      }
                 };

                 C c;

                 int main()  {
                     return 0;
                 }

                 The code generates the following error message:

                 exception system: exiting dues to multiple internal errors:
                         exception dispatch or unwind stuck in infinite loop
                         exception dispatch or unwind stuck in infinite loop

                 [CPP 5021]

        3.18 Enhancements, Changes, and Problems Corrected in
             Version 6.2-040

              Enhancements, changes, and problems corrected are as
              follows:

              o  In certain cases, dynamic initialization of a static
                 variable of aggregate type with an initializer list
                 containing both constant and non-constant values did
                 not occur correctly. Aggregate members initialized with
                 constant values were initialized with 0, not with the
                 constant values. Consider this example:

                     const float x = 3;

                     struct S {
                         static long *_GetEntries() {
                             static long _entries[] = { 2, (long)x, 8 };
                             return _entries;
                         }
                     }

                 In this example _entries[0] and _entries[2] were
                 not initialized correctly to 2 and 8, respectively.
                 Instead, the fields were both were incorrectly
                 initialized to 0.

                                                                      15

 






              The compiler inserts code into _GetEntries to
              initialize _entries the first time _GetEntries is
              called. Because it failed to insert the initializing
              code correctly, the code that initialized members with
              contant values was not being executed.

     3.19 Enhancements, Changes, and Problems Corrected in
          Version 6.2-037

           Enhancements, changes, and problems corrected are as
           follows:

           o  In certain cases, dynamic initialization of a static
              variable of aggregate type with an initializer list
              containing both constant and non-constant values did
              not occur correctly. Aggregate members initialized with
              constant values were initialized with 0, not with the
              constant values. Consider this example:

                  const float x = 3;

                  struct S {
                      static long *_GetEntries() {
                          static long _entries[] = { 2, (long)x, 8 };
                          return _entries;
                      }
                  }

              In this example _entries[0] and _entries[2] were
              not initialized correctly to 2 and 8, respectively.
              Instead, the fields were both were incorrectly
              initialized to 0.

              The compiler inserts code into _GetEntries to
              initialize _entries the first time _GetEntries is
              called. Because it failed to insert the initializing
              code correctly, the code that initialized members with
              contant values was not being executed.

           o  When generating EV6 code, the peephole optimizer
              could display an assertion failure complaining that
              an operand is not fixed or not float. This has been
              corrected. [6787]


     16

 






              o  When generating EV6 code, the compiler produced a code
                 pattern (specific to conversion between integer and
                 floating types) that could produce incorrect results.
                 This release corrects the problem. [6816]

              o  If the exception handling mechanism calls the two-
                 parameter delete operator to clean up an allocated
                 object that had an exception in the constructor, the
                 mechanism now passes the correct size to the second
                 (size) parameter. [6823]

              o  When compiling with -std arm, C++ treated the types
                 const char *&, and char *& as equivalent. Effects-
                 compatible types did not recognize this behavior. A
                 new ARM-compatible flag for types_are_compatible with
                 effects_compatible_types is now set when in ARM mode.
                 The new flag specifies that all type qualifiers are
                 ignored when comparing the type compatiblity of two
                 pointer or reference types. [6949]

                 The ARM mode of the compiler allows a const char *
                 reference to reference a char * object, as show in the
                 following example:

                 static char * f() {
                     char *value = 0;
                     const char * & d1 = value;  // d1 can reference value
                     d1 = "abc";                 // changes value
                     return value;               // should return "abc", not 0
                 }

                 In standard mode, however, this behavior is not
                 allowed, and the compiler did not recognize that
                 assignments to the reference change the value of the
                 object referenced. In the example, because the compiler
                 did not recognize that assignments to d1 would change
                 value, it assumed that the assignment to d1 did not
                 occur and that the correct return value fo the function
                 f() was 0.

                 This version of the compiler fixes the problem.

              o  A change in the debugging symbol table produced by
                 the C++ compiler causes all namespace members to
                 be generated in the local symbol table of the file
                 descriptor associated with the namespace, within the

                                                                      17

 






              scope of the namespace. This change make it easier to
              debug namespaces. [LDB1569]

     3.20 Enhancements and Changes in Version 6.2

           Version 6.2 includes the following enhancements and
           changes:

           o  Some functions needed for language compatibility run-
              time support have been moved from libcxxstd.a to the
              shared library libcxx.so. For details, see Deploying
              Your Application in Using Compaq C++ for Tru64 UNIX and
              Linux Alpha.

           o  Many compiler and library problems have been corrected
              (see Section 3.21 and Section 4.7).

           o  Many improvements have been made to cross-reference
              information generated by the compiler.

           o  The compilation system and run-time library now call
              destructors that are defined in shared images which
              have been closed correctly using dlclose(), with
              the linker option -depth_ring_search. This feature
              requires that a new libcxx be installed on your system
              with Version 6.2. Otherwise, the compiler reports the
              undefined symbol __cxx_call_static_dtors.

           o  The -gall option now outputs debugging information
              about unused variables, so that you can queries the
              debugger about them. For more information about this
              option, see Using the -gall and -gall_pattern Options
              in Using Compaq C++ for Tru64 UNIX and Linux Alpha.

           o  Debugging support for constant variables is improved.
              Although the compiler does not generate debug
              information for constant externs (because you might not
              be able to link), it does generate debug information
              for all constant variables whose underlying type is int
              or float

           o  Diagnostics from the driver during the link phase are
              now sent to stderr instead of to stdout.

           o  Consumption of virtual memory is significantly reduced
              when computing the addresses of deeply nested virtual
              base classes. [6473]

     18

 






              o  The compiler diagnoses more cases of unreachable
                 code. If you receive warnings you believe to be
                 inappropriate, please report them. [6534]

        3.21 Problems Corrected in Version 6.2

              This section summarizes compiler changes and the most
              important problems corrected in Version 6.2.

              o  Specifying -noglobal_array_new no longer causes
                 generation of rogue cleanup handlers. [6095]

              o  Enum types larger than int are now supported when
                 compiling with -std arm. [4499]

              o  Specifying -v now displays command-line, driver-
                 generated, and predefined macros on standard output.
                 The listing file now contains correct list of command-
                 line and predefined macros, taking into account macro
                 undefines and redefines. [4723] [5609]

              o  Within a template member function instantiation, the
                 compiler now correctly calls a function with short
                 pointer in -xtaso_short mode. The compiler no longer
                 displays an error for the call.

              o  Some compiler-generated wrapper functions with the
                 __STF____default_version  prefix were not resolved in
                 template automatic instantiation mode. The problem is
                 corrected. [6362]

              o  Debugging support is now provided for anonymous union
                 variables inside namespaces. In the following example,
                 debuggers support referencing s.a and s.b:

                 struct S {
                      union {
                          int a;
                          int b;
                      }
                 } s;

                 In the following example, the compiler generates two
                 variables, x and y, which the debuggers can examine.

                                                                      19

 






              union {
                  int x;
                  char y[4];
              };

              The compiler no longer generates tag names for tagless
              structs and unions.

           o  Under the following conditions, the compiler could
              generate code that returned the value of i before the
              store of the new value:

              1. Take the address of a variable, using a type other
                 than the variable's type, (p = (char *)&i).

              2. Assign to the variable using a pointer addition
                 expression, *(p + 0) = new_value.

              3. Fetch the variable's value directly (return i).

              The problem can occur only if the store using the
              pointer addition expression appears within an if
              statement, as in the following code:

              int f(int flag) {
                int len = 1;
                if (flag) {
                  char *ppp = (char *)&len;
                  *(ppp + 0) = 2;
                };
                return len;
              }

              The problem has been corrected. [6421]

           o  Bad code is no longer generated for an array reference
              within a template instantiation. [6394]

           o  The compiler no longer generates incorrect code for
              offsets to external arrays. [6386]

           o  The routine for new[] now calls delete[]  if an
              exception occurs during construction. [6243]

           o  A compiler crash caused by a label statement in a
              switch statement has been corrected. [6614]

     20

 






              o  Macro expansions are now output to the listing file
                 when both -show expansion and -source_listing are
                 specified. [6107]

              o  When a local stack is used in constructors, the
                 compiler displays the warning "Initialization of
                 references requires temporaries of automatic storage
                 duration". [4522]

              o  Null characters in comments are now ignored in -
                 std arm mode. The Version 6.0 compiler treated null
                 characters in comments as errors. Outside of comments,
                 null characters are now diagnosed as warnings in -std
                 arm mode, and as errors otherwise. [3740]

              o  The compiler has implemented the _poppar builtin
                 function and added code to convert output type for
                 _poppar, _popcnt, _leadz, and _trailz to match contents
                 of the UNIX builtins.h file. See  Built-In Functions in
                 Using Compaq C++ for Tru64 UNIX and Linux Alpha.

              o  A template class name can now be reused as a nontem-
                 plate class in a private namespace without generating
                 an error message. [6541]

              o  A Version 6.0 bug caused the the compiler to emit a
                 union layout incompatible with earlier versions if the
                 union contained bitfield of size 8, 16, 24 . . . up to
                 the size of the type for the bitfield. For example:

                 typedef struct size4 {
                         union {
                             unsigned ttn :8;
                             struct {
                                 unsigned incr :3;
                                 unsigned rep :5;
                             } v1;
                         } u;
                     } size4;

                 The size of size4 is 4 bytes for Version 5.7, and was
                 incorrectly set to 1 since Version 6.0. This bug is
                 fixed in Version 6.2. If you have such a bitfield in
                 your code, you must recompile. [6567]

                                                                      21

 






           o  If -nocleanup is specified, the compiler does not
              reference the destructors or delete operators used for
              cleanup code that is not generated. The -noexceptions
              option now implies -nocleanup. [6216]

           o  -std arm mode, the compiler no longer generates code to
              the left side of the -> and .  operators if the right
              hand operand is a static member. [4469]

           o  For compatibility with Version 5.6, the ec_inaccessible_
              base_class error on function return expressions in -std
              arm mode is now disabled. [3744]

           o  The compiler now warns about differences in meaningless
              qualifiers.

           o  The driver now terminates if the compilation results in
              a fatal error or ctrl-c.

           o  In -std arm mode, the compiler no longer checks for
              suitable copy constructors of classes with volatile
              qualifiers. [6087]

           o  To maintain compatibility with arm, cfront, and ms
              modes, null preservation code is enabled for cases
              where a pointer should not be null. [4695]

           o  The compiler now checks for comparison of two
              incompatible enums. The compiler reports this condition
              with a new informational message ec_incompatible_enum_
              comparison. [6172]

     3.22 Restrictions in Version 6.2

           This release is not totally compatible with previous
           versions; source changes might be required. The following
           general restrictions apply for the current release:

           o  The C++ International Standard permits overriding a
              virtual member function based only on a derived class
              return type. The current release does not support this
              capability.

           o  Intrinsic bcopy generates warning

     22

 






                 Starting with C++ Version 6.2, the bcopy function has
                 been made intrinsic to improve performance. On Compaq
                 Tru64 UNIX Version 4.n systems, this change can cause
                 the compiler to issue the following warning message:

                 cxx: Warning: /usr/include/strings.h, line 83: Expected type
                      "void (const void *, void *, unsigned long) C" is
                      incompatible with declared type "void (const char *,
                      char *, int) C", function will not be made intrinsic
                 extern void bcopy __((const char *, char *, int));
                 ------------^

                 Compaq Tru64 UNIX Version 4.n systems provide two
                 function prototypes for bcopy, one that conforms to
                 the standard, and another, the system default, for
                 compatibility with previous operating system versions.
                 The compiler issues the warning when it encounters
                 the nonstandard version. For details, see the bcopy(1)
                 reference page.

                 To suppress the message, you can do one of the
                 following:

                 o  Use an ANSI-standard copy function such as memcpy

                 o  Enable the standard function by defining -D_XOPEN_SOURCE_EXTENDED
                    -D_OSF_SOURCE before including the header file

                 o  Compile with the -std strict_ansi option

                 o  Use #pragma function(bcopy)

                 Because the next major operating system release
                 implements a change in the UNIX98 standards and
                 provides only the standard definition, the first or
                 second method is recommended. The third and fourth
                 methods prevent the function from being made intrinsic,
                 resulting in degraded performance.

              o  Some features implemented in Version 5.7 are not
                 supported by the current compiler. See Porting to
                 Compaq C++ in Using Compaq C++ for Tru64 UNIX and Linux
                 Alpha.

              o  Some objects might have their exception unwinding
                 information set to a negative index in the cleanup
                 table, resulting in a core dump at runtime if an
                 exception is raised. [7091]

                                                                      23

 






           o  The UNIX utility nm does not always work on Compaq
              Tru64 UNIX Version 4.n systems with object files
              generated by the current compiler. The symptom is a seg
              fault when nm attempts to dump its list. An alternative
              to nm might be the odump utility. For example, the
              command odump -tv foo.o lists all the symbols in the
              archive. See the odump reference page for more details
              on the odump utility. Another possible workaround is
              to compile your object file with -g (debugging), then
              recompile it without -g. That procedure might avoid
              triggering the nm bug.

              If you want to obtain a version of nm that corrects
              this problem, these are the patch kit identifiers:

              _______________________________________________________
              OPERATING_SYSTEM_VERSION__PATCH_ID_____________________

              v40                       OSF400-438

              v40a                      OSF405-438

              v40b                      OSF410-438

              v40c                      OSF415-438

              v40d______________________OSF420-42____________________

           o  If you use a non-default pointer size or member
              alignment and header files are not protected, the
              following warning is issued:

                 < cxx: Warning: A non-default pointer size or member alignment is
                 specified and the system header files are not protected. This may
                 yield unpredictable results. The protect_headers_setup script can
                 help. See the protect_headers_setup(8) reference page for details.

              The protect_headers_setup(8) reference page page is
              planned for a future release of Compaq Tru64 UNIX.
              For now, see Protecting System Header Files in  Using
              Compaq C++ for Tru64 UNIX and Linux Alpha.

           o  Restricted address space size for precompiled headers
              in some versions of Compaq C++.

              Some versions of Compaq C++ might restrict the size
              of the address space available for use by precompiled
              headers. If the compiler terminates with a message
              about mapped memory, this may be the problem.

     24

 






                 To increase the address space available for precompiled
                 headers you need to increase the mapentries limit.

                 Follow these steps to change the mapentries limit:

                 1. Become the root user.

                 2. Create a new file named /tmp/xxx and insert the
                    following lines:

                    vm:
                     vm-mapentries=5000

                 3. Execute the sysconfigdb command as follows:

                    # /sbin/sysconfigdb -f /tmp/xxx -m vm

                 4. Reboot the system.

                 This procedure increases the mapentries limit from
                 the default 200 to 5000. Increasing the limit by that
                 amount has no adverse effect on the system.

              o  When using PCH, the line number associated with an
                 inline function is the line at which the PCH stop is
                 encountered.

              o  Certain utilities, such as GNU Make, do not recognize
                 compressed object files, which the compiler creates by
                 default. If you encounter problems, you can specify the
                 -nocompress command-line option.

              o  Instantiating function templates with array types can
                 result in different external name encoding than with
                 C++ Version 5.n. To avoid link errors, recompile the
                 template definition with the current version of the
                 compiler.

              o  Linker -no_archive does not work with Compaq C++

                 The switch does not work because the Standard Library,
                 libcxxstd.a, is supplied only in archive form.

                 Specifying -no_archive causes the cxx drive to issue
                 the following messages:

                 ld (prelink):
                 Can't locate file for: -lcxxstd
                 ld:
                 Can't locate file for: -lcxxstd

                                                                      25

 






           o  Class and Standard Libraries generate Third Degree
              messages. Appendix C in Using Compaq C++ for Tru64 UNIX
              and Linux Alpha describes these messages.

     3.23 Problems Corrected in Version 6.1-029

           This section summarizes compiler changes, enhancements,
           and the most important problems corrected in Version 6.1-
           029.

           o  The optimization phase of the compiler has been changed
              to disable a specific optimization that caused ATOM
              based tools to behave unpredictably. This optimization
              may be restored once these tools have been enhanced to
              expect this optimization.

           o  New warning messages indicate when assigning from a
              larger to a smaller data type might cause a truncation.
              These messages facilitate porting from 32-bit to 64-bit
              platforms. [3971]

           o  A workaround has been implemented to prevent the linker
              from erroneously declaring too many GOTs during the
              prelink phase. [6027] [43-4-305]

           o  Templates made friend are now instantiated with
              external linkage when -timplicit_local is specified.
              [6056]

           o  Access checking for pointer to members in ARM mode has
              been relaxed to be more compatible with Version 5.n.
              [6088]

           o  Calling operator(new) on an array of objects allocates
              extra header information to describe the array so that
              operator delete can call destructors on the elements.
              In this release, the header has been made compatible
              with object code generated with version 5.n releases.
              [6151]

           o  During the prelink phase, the driver no longer splits
              linker output lines at 8000 characters. [6166]

           o  The driver no longer suppresses error messages during
              the prelink phase. As a result, messages might apprear
              multiple times. This new behavior helps prevent silent
              or confusing failures. [6168]

     26

 






              o  A problem unwinding from multiple exceptions has been
                 corrected. [6185]

              o  A compiler fatal error using volatile structures has
                 been corrected. [6186]

              o  The cxx driver no longer runs post-link phases that are
                 unnecessary to determine required templates. [6191]

              o  A problem with interaction between -vptr_size_short and
                 -xtaso_short has been corrected. [6195]

              o  If a local static object is referenced by more than
                 one template, the compilation no longer results in an
                 unresolved symbol for the __fini routine. The routines
                 to call the destructors for static objects, which are
                 prefixed with __fini, are now allocated properly with
                 automatic instantiation mode. [6278]

        3.24 Problems Corrected in Version 6.1

              This section summarizes compiler changes, enhancements,
              and the most important problems corrected in Version 6.1.

              o  The Version 6.0 compiler incorrectly mangled the name
                 of a class virtual function table when that class was
                 nested within another class or namespace. If object
                 modules compiled with Version 5.n and Version 6.0
                 were linked together, the compiler might display the
                 following message:

                 ld:
                 Unresolved:
                 std::__vtbl_3std9type_info

                 This problem has been corrected. Any code generated
                 with Version 6.0 that demonstrates this problem should
                 be recompiled with the current compiler. [5144]

              o  The compiler used to mark all member functions of
                 the class that had not already been specialized as
                 needing to be instantiated when processing a #pragma
                 define_template class <args>. But the compiler did
                 not instantiate the functions until processing the end
                 of the scope. If a specialization occurred after the
                 #pragma but before the compiler tried to instantiate
                 it, the compiler found that the member function had

                                                                      27

 






              already been specialized and reported the following
              error:

              "function" cannot be instantiated -- it has been explicitly specialized

              This error is reduced to a warning and is issued only
              once per instantiation. The warning can be suppressed
              by using the command-line switch -msg_disable 490. See
              Compaq C++ Implementation in Using Compaq C++ for Tru64
              UNIX and Linux Alpha. [43-4-137]

           o  The compiler no longer generates incorrect code when
              dereferencing an element of an array of pointers.
              [5236]

           o  A problem creating shareable libraries has been
              corrected by allocating static local const variables
              initialized with pointers to .rdata instead of to
              .rconst. [43-4-166]

           o  To facilitate setting default compiler flags, you
              can now create an optional configuration file named
              comp.config or an environment variable named DEC_CXX.

              -  The comp.config file allows system administrators
                 to establish a set of compilation flags that
                 are applied to compilations on a system-wide
                 basis. The compiler flags in comp.config must be
                 specified on a single line, and the comp.config file
                 should be stored in the compiler target directory,
                 /usr/lib/cmplrs/cxx.

              -  The DEC_CXX environment variable allows users to
                 establish a set of compilation flags that are
                 applied to subsequent compilation on a per user
                 basis.

                 The DEC_CXX environment variable can contain two
                 distinct sets of compilation flags separated by
                 a single vertical bar ( | ). The flags before the
                 vertical bar are known as prologue flags and the
                 flags after the bar are know as epilogue flags.

                 The DEC_CXX environment variable can begin or end
                 with a vertical bar, or have no vertical bar at
                 all. If no vertical bar is present, the flags are
                 treated as prologue flags by default. Any vertical

     28

 






                    bar found after the first vertical bar is treated as
                    whitespace and a warning is issued.

                 During a compilation, compiler flags are processed in
                 the following order:

                 1. comp.config flags

                 2. DEC_CXX prologue flags

                 3. command line flags

                 4. DEC_CXX epilogue flags  If -v is specified on
                    the command line, the contents of DEC_CXX and
                    comp.config, if present, are displayed. [4488]

              o  By default, C files are compiled with -std. Users can
                 now override the default by specifying -std0/-std1.
                 [4392]

              o  The compiler no longer mishandles "?" operations on a
                 boolean type in constructs like that in the following
                 example. [43-4-135]

                 bool f(int i)
                 {
                    return (i<5 ? false : true );
                 }

              o  Parallel compiles now work correctly because the com-
                 piler no longer deletes an empty template repository.
                 [5544]

              o  The current version does not support the -show
                 statistics option implemented in Version 5.7.

                 The following are now supported:

                    -nocpp
                    -show expansion
                    -xref
                    -xref_stdout
                    listing of predefined macros
                    #pragma message

                                                                      29

 






     3.25 Enhancements and Changes in Version 6.0

           This section briefly summarizes changes and enhancements
           made in Version 6.0. For information about compatibility
           issues that you might encounter using Version 6.2 if you
           have used Version 5.n in the past, refer to Porting to
           Compaq C++ in Using Compaq C++ for Tru64 UNIX and Linux
           Alpha.

           o  Support for the C++ International Standard (with some
              differences, as described in Section 2.3), including
              the C++ Standard Library. See Section 4 for information
              about and changes to the Standard Library.

           o  Language mode options

              For compatibility with previous versions, the compiler
              supports an ARM language mode and provides both -std
              ansi and -std arm language mode options, as well as
              options to support other C++ dialects. For details,
              see Porting to Compaq C++ in Using Compaq C++ for Tru64
              UNIX and Linux Alpha.

           o  Improved automatic instantiation of templates,
              including fewer restrictions. In particular, Compaq
              C++ no longer requires that template declarations and
              definitions appear in header files. For details, see
              Using Templates in Using Compaq C++ for Tru64 UNIX and
              Linux Alpha.

           o  Support for precompiled headers to decrease compilation
              times. For complete information, refer to Precompiled
              Headers in Using Compaq C++ for Tru64 UNIX and Linux
              Alpha.

           o  Performance optimization options

              To improve performance, the compiler provides the
              following options:

              o  -[no]ansi_alias

              o  -assume [no]pointers_to_globals

              o  -assume [no]whole_program

              For details, see the cxx(1) reference page.

           o  Run-Time type identification

     30

 






                 The compiler emits type information for Run-Time
                 type identification (RTTI) in the object module with
                 the virtual function table, for classes that have
                 virtual function tables. For details, see Run-Time
                 Type Identification in Using Compaq C++ for Tru64 UNIX
                 and Linux Alpha.

              o  Changes to behavior of the -gall option. See Using the
                 -gall and -gall_pattern Options in Using Compaq C++ for
                 Tru64 UNIX and Linux Alpha.

        4 Release Notes for the C++ Standard Library

              The following sections describe enhancements, changes,
              problems corrected, and restrictions for the C++ Standard
              Library. For information about the Compaq C++ Class
              Library, see Appendix A in Using Compaq C++ for Tru64
              UNIX and Linux Alpha.

              The current version of Compaq C++ implements the new
              Standard Library string class, known as the String
              Library. Do not confuse this class with the String
              Package, which is part of the Compaq C++ Class Library
              implemented in earlier versions of Compaq C++.

              Portions of the ANSI C++ Standard Library have been
              implemented in Compaq C++ using source licensed from
              and copyrighted by Rogue Wave Software, Inc. Information
              pertaining to the C++ Standard Library has been edited and
              incorporated into Compaq C++ documentation with permission
              of Rogue Wave Software, Inc. All rights reserved.

              Portions copyright 1994-2002 Rogue Wave Software, Inc.

        4.1 Enhancements, Changes, and Problems Corrected in 6.5-020

              o  When called with a null string, the basic_stringbuf::str(const
                 string_type& str) method was not setting the underlying
                 character buffer to zero length. It has been fixed.
                 [10.1674]

              o  <new> and <new.hxx> library headers have been modified
                 to suppress "support for placement delete is disabled"
                 informational message at the point of declaration of

                                                                      31

 






              nothrow version of operator delete and nothrow version
              of array delete. [10.1675]

     4.2 Enhancements and Changes, and Problems Corrected in Version
         6.5

           Enhancements, changes, and problems corrected are as
           follows:

           o  The library header and template definition files have
              been modified to compile in STRICT_ANSI mode with
              the Version 6.5 compiler. Modification was necessary
              because Version 6.5 enforces more stringent language
              rules in some cases than previous versions. [10.1649]

           o  The deallocate() member function of the allocator
              class in the <memory> header has been modified so that
              operator delete is not called with the null pointer.
              Although calling delete with the null pointer is
              legal in Compaq C++, the Third Degree tool on Tru64
              UNIX issues a warning when such a call is made. The
              modification was made to avoid the warning. [10.1657]

     4.3 Enhancements, Changes, and Problems Corrected in Version
         6.3

           Version 6.3 includes the following enhancements:

           o  The tree data structure, which sets and maps usage, has
              been refined to decrease the amount of space allocated
              for small element size containers. [10.1475]

           o  To ensure thread safety, the basic_string reference
              count used to be protected by a mutex, which called
              thread locking and unlocking routines. Performance
              of this class in multithreaded applications has been
              improved by changing the implementation to use instead
              atomic builtins (see Appendix B in Using Compaq C++ for
              Tru64 UNIX and Linux Alpha).
              [10.1138]

           Version 6.3 corrects the following problems:

           o  The Standard Library vector class now allocates space
              correctly for elements greater than 1024 bytes; runtime
              core dumps caused by incorrect allocation in previous
              versions no longer occur. [10.1459]

     32

 






              o  The iostreams and locales are now multi-thread safe.
                 [10.1429]

              o  Compiling a program in -std strict_ansi mode using
                 the basic_fstream class no longer causes run-time seg
                 faults or core dumps. [10.1357]

              o  The basic_string::find_first_not_of(charT, size_type)
                 function now works correctly if the string contained
                 embedded nulls. [10.1316]

              o  The Version 6.2 string extraction operator no longer
                 removes the extra space at the end of the string, as in
                 the following example

                     ifstream inFile("input.dat"); // input.dat contains "abc de"
                     inFile >> word; // read "abc"
                     inFile.get(ch1); // ch1 should be space, was 'd'

                 [10.1300]

              o  Two of the basic_string::compare() member functions no
                 longer throw an exception if the length of the second
                 string is longer than the length of the current string.
                 They no do so only if the position the user specifies
                 within the second string is greater than the length of
                 the second string. [10.1298]

              o  The prototype for the set_new_handler() is now
                 included in the <new> header file when you specify
                 -nostdnew on the command line.

              o  The basic_string::resize() member function now works
                 correctly. If two strings point at the same underlying
                 char* and the resize() function is called on one of
                 them, you can change the underlying string for one of
                 the strings without affecting the value of the other.

              o  You can now call the algorithm stable_sort() more than
                 once with the same container without causing a seg
                 fault.




                                                                      33

 






     4.4 Restrictions in Version 6.3

           Restrictions are as follows:

           o  When using the Standard Library iostreams for
              interactive input to cin from a terminal, a user may
              have to type more than one Ctrl D to indicate end-of-
              file. [10.1413]

           o  Currently you might encounter compilation errors if you
              try to use a user-defined allocator and pointer class
              with the STL containers. This problem will be fixed in
              a future release. [10.1430]

     4.5 Enhancements, Changes, and Problems Corrected in Version
         6.2-037

           Enhancements, changes, and problems corrected are as
           follows:

           o  Fix for unexpected null cleanup block error

              When an exception was raised and caught in the catch
              clause at runtime, some loops with a try-catch block
              would generate an internal error about an unexpected
              null cleanup block. This error was caused by the
              runtime environment and has been corrected.

           o  Fix for raw_storage_iterator assignment operator

              In versions 6.2 and earlier, a problem in the
              assignment operator for the class raw_storage_iterator
              could cause a run-time seg fault if, for example, you
              called the algorithm stable_sort() more than once with
              the same container. The problem has been corrected.
              [10.1284]

           o  Fix for basic_string::compare() member functions

              In version 6.2, two of the basic_string::compare()
              member functions were throwing an exception if the
              length of the second string was longer than the length
              of the current string. This has been fixed so that
              they throw an exception only if the position the user
              specifies within the second string is greater than the
              length of the second string. [10.1287]

           o  Fix for basic_string::resize()

     34

 






                 A problem in the basic_string::resize() member
                 function in Version 6.2 has been corrected. The
                 incorrect behavior was that if two strings pointed at
                 the same underlying char*, and the resize() function
                 was called on one of them, and if you then changed
                 the underlying value for one string, the value for the
                 other string would also be changed. [10.1287]

              o  Fix to string assignment operator when assigning string
                 with embedded nulls

                 A problem in the basic_string assignment operator
                 prevented strings containing embedded nulls from being
                 copied correctly. The problem has been corrected.
                 [10.1238]

              o  Fix for missing set_new_handler() prototype when
                 specifying -nostdnew

                 The prototype for the set_new_handler() function was
                 missing from the <new> header file if you specified
                 -nostdnew on the command line. The problem has been
                 corrected.

        4.6 Enhancements and Changes in Version 6.2

              The following enhancements and changes are included in
              Version 6.2:

              o  Cleaner header file inclusion policy

                 This new version of the Standard Library is much
                 cleaner in its inclusion of unnecessary headers.
                 For example, the header file <algorithm> no longer
                 includes <functional>. <ostream> and <istream> no
                 longer include <locale>. Programs that used to count on
                 these inclusions might break. You can correct them by
                 explicitly including any header files you use in your
                 own sources.

              o  New interface to get_temporary_buffer and use_facet

                 Because the Version 6.2 C++ compiler now supports
                 explicit template function arguments, it also supports
                 the standard interface to the get_temporary_buffer()
                 function. The following example shows how code must
                 change:

                                                                      35

 






              Change this:

              get_temporary_buffer(len,(T*)0); // two arguments

              to this:

              get_temporary_buffer<T>(len); // one argument

              where "T" is the value type of the container.

              The standard interface to the locale class use_facet()
              function is also now supported. The following example
              shows how code must change:

              Change this:

              use_facet(loc,(ctype<char>*)0);

              to this:

              // use_facet only takes one argument
              use_facet<ctype<char> >(loc);

           o  Many common iostream and locale instantiations (for
              example, those based on the char type) have been put
              into the Standard Library to improve compile-time
              performance. If you want to instantiate them yourself
              and use your own instantiations (perhaps to have a
              debugging version), follow these steps:

              1. Compile with the macro __FORCE_INSTANTIATIONS
                 defined (-D__FORCE_INSTANTIATIONS).

              2. Link with the option -nopreinst. The linker then
                 finds the instantiations in your repository before
                 it finds those in the Standard Library.

     4.7 Problems Corrected in Version 6.2

           The following problems are corrected in Version 6.2:

           o  money_get/money_put locale facets now conform to C++
              International Standard

              The money_get and money_put locale facets have been
              corrected to match the standard. In the previous
              version, for example, money_get appeared as:

     36

 






                 template <class charT,
                      bool Intl = false,
                      class InputIterator = istreambuf_iterator<charT> >
                 class money_get;

                 They now correctly match the standard, where the
                 interface appears as:

                 template <class charT,
                      class InputIterator = istreambuf_iterator<charT> >
                 class money_get;

                 Note that the second template argument "Intl" has been
                 removed. The member functions get() and put() now
                 accept Intl as an argument.

              o  ios_base::openmode flags set to conform to Standard

                 The standard file stream classes have been corrected
                 to conform to the Standard with regard to setting the
                 ios_base::openmode flags. In the previous release, it
                 was possible to create a file for reading and writing
                 with this code:

                 #define __USE_STD_IOSTREAM
                 #include <stdlib.h>
                 #include <fstream>

                 int main() {
                         fstream fs("foo.out", ios_base::in
                                 | ios_base::out);
                         fs << "abc" << endl;
                         return EXIT_SUCCESS;
                 }

                 In the current release, this code works only if the
                 file already exists. If the file does not exist, you
                 need to also specify ios_base::trunc; that is, you must
                 change the first line in main() to:

                 fstream fs("foo.out", ios_base::in | ios_base::out
                            | ios_base::trunc);

                 This conforms to table 92 in the Standard, which
                 specifies the "C" equivalent of the File open modes.

              o  Correction to list::sort(Compare)

                                                                      37

 






              A bug in the list::sort(Compare comp) member function
              is corrected. Previously, if users supplied their own
              Comparison function object for the element of the list,
              the compiler issued a message stating that it required
              an operator< defined for the element type. This no
              longer occurs.

           o  reverse_iterator now matches the Standard

              reverse_iterator has been changed to match the
              standard. It now takes only one template argument
              of type iterator instead of five. Users must change
              existing code to remove the additional unnecessary
              arguments.

           o  bitset constructors no longer accept a const char

           o  A bitset can no longer be constructed with a const
              char* argument. For example, the following no longer
              compiles:

              bitset<32> b("111111111");

              The constructor that takes a string is a templatized
              constructor, and thus can perform type deductions only
              on exact matches, not conversions (for example, const
              char* to string). To make the code in the previous
              example compile with the current version, the argument
              must be explicitly cast to a string, as follows:

              bitset<32> b( string("111111111"));

           o  assign(size_t) removed from vector, deque, list

              Previous releases of the Standard Library contained
              a member function called assign() inside the vector,
              deque, and list classes. This function accepted only
              a size_t argument. This has been removed, because it
              is not in the Standard. You must add an extra argument
              indicating the value you want assigned. For example,
              you change calls like the following:

              v.assign(5); // where v is a vector<int>

              to:

              v.assign(5, int());

           o  allocator<>::deallocate(pointer) removed

     38

 






                 The member function allocator<>::deallocate(pointer)
                 has been removed. The Standard requires two arguments
                 for this member function. The second argument should
                 be of size_type and have the same value as the first
                 argument passed to allocator<>::allocate().

              o  basic_ios now initializes skipws|dec

                 To conform to the Standard, the following basic_
                 ios constructor constructs a basic_ios object and
                 initializes the format control bits to skipws | dec:

                   explicit basic_ios(basic_streambuf<charT, traits>*sb)

                 Previously ,this constructor also initialized the bit
                 indicating that output is right justified. Because the
                 constructor is called while constructing any of the
                 IOStream objects cout, clog, cerr, wcout, wclog, or
                 wcerr, the difference is apparent if you examine the
                 format control bits set after initializing one of these
                 objects.

                 Consider the following program:

                 #include <stdlib.h>
                 #include <iostream>
                 using namespace std;
                 int main()
                 {
                     cout << cout.flags() << endl;
                     cout << clog.flags() << endl;
                     cout << cerr.flags() << endl;
                     cout << wcout.flags() << endl;
                     cout << wclog.flags() << endl;
                     cout << wcerr.flags() << endl;
                     return EXIT_SUCCESS;
                 }

                 The output now indicates that only the skipws and dec
                 format control bits are initialized. Previously it
                 would have indicated that the right bit was also set.

              o  Some iterator classes removed

                 The following classes no longer exist in the Standard
                 and have been removed from library headers.

                    reverse_bidirectional_iterator

                                                                      39

 






                 random_access_iterator
                 bidirectional_iterator
                 forward_iterator
                 output_iterator
                 input_iterator

              Use instead the template class iterator with the
              template argument category to indicate which type of
              iterator you are constructing.

           o  The default allocator argument changed for basic_string

              The default allocator argument for the class basic_
              string has been changed from allocator<void> to
              allocator<charT>. Any STL container constructed with an
              allocator<void> template argument no longer compiles,
              because the specialization of allocator<void> does not
              contain all the necessary typedefs.

           o  strstream now deletes underlying strstreambuf

              A problem has been corrected in the Standard Library
              strstream classes that prevented underlying strstream-
              buf (and thus the string) from being deleted when the
              strstream object was destroyed. The standard states
              that they should be deleted if strmode & allocated is
              true and strmode & frozen is not true.

              For example:

              #define __USE_STD_IOSTREAM
              #include <strstream>

              void func()
              {
                ostrstream myostr;
                myostr << "abc";
              }

              If you called func() the string "abc" was never
              deleted when the myostr stream was destroyed. This
              problem has been corrected. Note that the Class Library
              strstream classes have always deleted the underlying
              string.

           o  sync_with_stdio() function is static

     40

 






                 In previous versions, the function sync_with_stdio()
                 was incorrectly declared as a member function of ios_
                 base. The function is now correctly defined as a static
                 member function; it is no longer necessary to call it
                 with the "->" or or "." notation.

        4.8 Restrictions in Version 6.2

              This section describes problems you might encounter when
              using the current release of the C++ Standard Library with
              the Compaq C++ compiler. Where appropriate, workarounds
              are suggested.

              o  Do Not Use Standard Library template Definition File
                 Names

                 The Standard Library supplies the following template
                 definition files in /usr/include/cxx:

                 algorithm.cfstream.cc streambuf.cvector.cc  time.cc
                 bitset.cc  ios.cc     locimpl.cc string.cc  ctype.cc
                 istream.cc numbrw.cc  tree.cc    collate.cc messages.cc
                 complex.cc iterator.ccostream.cc valarray.ccmoney.cc
                 deque.cc   list.cc    sstream.cc valimp.cc  numeral.cc
                 rwlocale.cc

                 If you use the same prefix name for any of your local
                 files and have the directory that contains them in
                 your include search path before /usr/include/cxx, the
                 automatic instantiation mechanism picks up your local
                 copy and does not correctly find the library files.
                 (See Using Compaq C++ for Tru64 UNIX and Linux Alpha
                 for more information about how the prelinker finds
                 template definition files.)

                 Do not use any of these names as source file names for
                 your application.

              o  Redeclaration of Standard Library Functions

                 Many of the prototypes in the Standard Library have
                 been changed to conform to the C++ International
                 standard by the addition of exception specifications.
                 This means that if you have redeclared the declarations
                 in your own code, you need to add the correct exception
                 specification in order to match what's declared in the
                 header.

                                                                      41

 






              For example:

              #include <new.h>

              // override default operator new
              // this gives an error
              inline void* operator new(size_t s);

              To prevent this, you'd need to change your new()
              declaration to:

              inline void* operator new(size_t s) throw(std::bad_alloc);

           o  Files/Macros for Internal Use Only

              Compaq C++ Version 6.1 ships the following non-Standard
              headers which are for internal use only. Their contents
              are subject to change and can not be relied upon.

              <stdcomp>     <stl_macros>   <stddefs>    <compnent.hxx>

              <stdmutex>    <stdexcept>    <lochelp>    <locimpl>

              <locimpl.cc>  <valimp>       <valimp.cc>  <vendor>

              <codecvt>     <codecvt.cc>   <collate>    <collate.cc>

              <ctype>       <ctype.cc>     <locvector>  <math>

              <messages>    <messages.cc>  <money>      <money.cc>

              <numeral>     <numeral.cc>   <random>     <rwcats>

              <rwdispatch>  <rwlocale>     <rwlocale.cc><rwstderr>

              <rwstderr_    <string_ref>   <time>       <time.cc>
              macros>

              <traits>      <usefacet>

              In addition both Standard and non-Standard headers make
              use of macros beginning with _RW or __RW. These _RW*
              and __RW* macros are for internal use only. They are
              subject to change and can not be relied on.

           o  The size of long double has changed in Compaq Tru64
              UNIX Version 5.0. If you are using the standard
              iostreams or locale library for inputting or outputting
              long doubles, you must specify -nopreinst on your link
              line to obtain instantiations that work correctly.

           o  Use of exception in <math.h> and Standard C++ Library

     42

 






                 In Compaq C++ Version 6.1, namespaces resolve a
                 conflict between the name exception found in the header
                 <math.h>, which represents a structure, and the name
                 exception found in the C++ Standard Library header
                 <exception>, which represents the Standard Library
                 exception class. The structure exception from <math.h>
                 is visible in the global namespace. The Standard
                 Library exception class from <exception> is visible
                 in the std namespace.

                 Because of this behavior, if you include, directly
                 or indirectly, both of the headers <math.h> and
                 <exception> you must qualify actual uses of exception
                 to avoid name conflicts:

                      #include <math.h>
                      #include <exception>
                      int main () {
                        ::exception e;     // exception from math.h
                        std::exception e1; // Standard Library exception class
                        return 0;
                      }

              o  collate_byname<wchar_t>::do_transform()

                 The function collate_byname<wchar_t>::do_transform()
                 seg faults if you use it with any locale other than
                 the "C" locale. This happens because of a bug with
                 the underlying C function wcsxfrm(). No workaround
                 currently exists for this problem.

              o  ctype_base::graph

                 In the current implementation of the ctype_base class,
                 a character has a graph property if and only if it
                 also has an alpha, a digit or a punct property. Thus,
                 mathematical and scientific symbols and dingbats
                 from the UNICODE character set will not be classified
                 properly.

              o  IOStreams cannot output IEEE NaNs/Infinities

                 The Standard IOStreams Library does not support output
                 for IEEE NaNs and Infinities.

              o  ios_base::out does not truncate a file to zero length

                                                                      43

 






              The ios_base::openmode ios_base::out should open a
              file for output. This means that the file is either
              truncated to zero length if it exists or created for
              writing if it does not. Therefore ios_base::out is the
              same as ios_base::out | ios_base_trunc.

              With our sources, the following program behaves
              incorrectly.

              #include <stdlib.h>
              #include <iostream>
              #include <fstream>
              using namespace std;
              int main()
              {
                  fstream fs ("t.in",ios_base::out);
                  fs << "A";
                  return EXIT_SUCCESS;
              }

              Where t.in contains xyz.

              After running this program, t.in contains

                   Ayz

              It should contain

                   A

              You can work around this problem by replacing ios_
              base::out with ios_base::out | ios_base::trunc.

           o  Overriding operator new in library

              You can define a global operator new() to displace the
              version used by the C++ Standard Library or C++ Class
              Library. For instructions, see Overriding operator(new)
              in Using Compaq C++ for Tru64 UNIX and Linux Alpha.

           o  The -define_templates and -tall options are not
              guaranteed to work with the Standard Library. Use
              automatic instantiation or specify -tused instead.

              When compiled with -define_templates or -tall, the
              following code generates compilation errors indicating
              that no operator "<" (and ">" or "+" or "-") matches
              these operands:

     44

 






                  #include <map>
                  map<int,int> foo;

                 The instantiation options are not guaranteed to work
                 with the Standard Library because they request the
                 compiler to instantiate all templates, even those that
                 are not used.

                 The -tall option does not work because rb_tree, the
                 underlying implementation of map and set supports
                 a bidirectional iterator class. Thus, operator+,
                 operator-, operator< and operator> are not defined
                 in the iterator for that class.

                 When you instantiate the tree with cxx -tall or
                 cxx -define_templates, the compiler attempts to
                 instantiate recursively everything that is typedefed,
                 even if not used. Thus, the tree contains a typedef
                 for std::reverse_iterator<iterator>, which then
                 instantiates the global class reverse_iterator
                 with the tree iterator as the template argument
                 RandomAccessIterator, a misnomer in this case.

                 This behavior generates undefined symbols for
                 these operators because they are used within the
                 definition of the operator member functions inside
                 reverse_iterator. The compiler therefore attempts to
                 instantiate them even though they do not exist.

                 Specifying -tused for the Standard Library directs the
                 compiler to only instantiate those templates that are
                 used.

              o  Description of the initial state of the stringstream
                 ctor

                 There has been some controversy in the comp.lang.c++
                 reflector and within the standards committee on the
                 semantics of the stringstream constructor. Consider the
                 following example:

                 #define __USE_STD_IOSTREAM
                 #include <stdlib.h>
                 #include <sstream>

                                                                      45

 






              int main() {
                  ostringstream ost("Hello, ");
                  // ost.rdbuf()->pubseekoff(0,ios::end,ios::out);
                  ost << "world!";
                  cout << ost.str() << endl;
                  return EXIT_SUCCESS;
              }

              Depending on the setting of the streambuf put pointer
              after the initial construction, the program could print
              either "Hello, world!" or "world!". The Rogue Wave (and
              Compaq C++) interpretation is that the stringstream
              constructor does not change the initial position of the
              streambuf pointer, so that the program prints "world!".

              If you want to change the setting of the put pointer
              to match the other interpretation (that the pointer
              should move to the end of the initializer string), you
              must insert a call to pubseekoff(), as shown in the
              commented line.

              If the ANSI C++ committee issues a clarification on
              this matter Compaq C++ will implement their decision.

           o  Linker might produce multiply defined symbols from
              Standard Library

              The linker might produce multiply defined symbols from
              the Standard Library when linking against your own
              shared library or libraries. If you find multiply
              defined symbols like the following coming from
              libcxxstd.a, you might be creating one or more shared
              libraries and then using those shared libraries to
              create an executable.

              ld:
              /usr/lib/libcxxstd.a(typeinfo.o):
                   std::__vtbl_3std9type_info: multiply defined
              /usr/lib/libcxxstd.a(vec_newdel.o):
                   __vec_new_eh: multiply defined

              The problem is that libcxxstd.a is an archive library.
              When you create a shared object that references this
              library, the symbols are pulled into that shared
              object. When you then use the shared library, it
              finds the symbol both in your shared object and in

     46

 






                 the libcxxstd.a library archive. To work around this
                 problem, follow these steps:

                 1. If you are creating multiple shared libraries,
                    create them without linking in the libcxxstd library
                    and with the expect_unresolved ld flag to prevent
                    linker errors. For example:

                      cxx -shared -nocxxstd -expect_unresolved "*std*" -o libA.so obj1.o
                      cxx -shared -nocxxstd -expect_unresolved "*std*" -o libB.so obj2.o
                      .
                      .
                      .

                 2. Link the final executable normally, so that
                    unresolved symbols from libcxxstd are linked in.
                    For example:

                      cxx -L. main.cxx -lA -lB

                 A release of libcxxstd as a shared library is planned
                 once once the library interface is stablilized.

              o  Compilation warnings and errors with auto_ptr

                 Using auto_ptr in non strict_ansi mode generates
                 warnings about initializing a non-const ref with
                 an lvalue. These warnings are due to the lack of
                 enforcement of the rule in the C++ standard that
                 binding a reference to a non const to a class rvalue
                 is illegal. To make auto_ptr work correctly, you must
                 compile the module(s) that use auto_ptrs in ansi or
                 strict_ansi language mode.

                 In strict_ansi mode, you may still encounter compila-
                 tion errors when converting an auto_ptr<Derived> to an
                 auto_ptr<Base>. For example, this does not work:

                     struct Base {};
                     struct Derived : Base {};

                     auto_ptr<Derived> source2() {return auto_ptr<Derived>(new Derived);}



                                                                      47

 






                  int main() {
                    auto_ptr<Derived> d;
                    auto_ptr<Base> b(d); // compiles
                    auto_ptr<Base> p3(source2()); // doesn't compile
                    return 0;
                  }

              This is a known deficiency of the auto_ptr class, see
              language issue 84 at:

                 http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/core-issues.htm

              for a discussion of the problem. You must either use
              casts or avoid temporaries under these conditions.

              Remember that you should not use auto_ptrs as elements
              of an STL container, because they do not meet the
              CopyConstructible and Assignable requirements for
              Standard Library container elements. Compilation
              warnings occur if, for example, you try to insert an
              auto_ptr into a container. See

                http://www.gotw.ca/gotw/025.htm

              and

                http://www.awl.com/cseng/titles/0-201-63371-X/auto_ptr.html

              for discussions of the history and current restrictions
              of the auto_ptr class.

     4.9 Enhancements and Changes in Version 6.1-029

           The following enhancement is included in Version 6.1-029:

           o  Smaller executables for users of the basic_string
              library component

              The Standard Library now provides a better separation
              of the STL and Standard IO components. As a result,
              users of the basic_string component of the Standard
              Library should obtain smaller executables. In Version
              6.1, using only a string in an application caused all
              iostreamand locale object files from the Standard
              Library to be included in the executable. These
              unnecessary files are no longer included.

     48

 






        4.10 Problems Corrected in Version 6.1-029

              The following problems are corrected in Version 6.1-029:

              o  list::sort(Compare comp) member function now correct

                 Previously, if users supplied their own Comparison
                 function object for the element of the list, the
                 compiler still required an operator< defined for the
                 element type. This is no longer the case.

              o  strstream now correctly deletes underlying strstreambuf

                 The Standard Library strstream classes now delete the
                 underlying strstreambuf (and string) when a strstream
                 object is destroyed. The standard states that they
                 should be deleted if strmode & allocated is true and
                 strmode & frozen is not true.

                 For example:

                 #define __USE_STD_IOSTREAM
                 #include <strstream>

                 void func()
                 {
                   ostrstream myostr;
                   myostr << "abc";
                 }

                 If you called func() the string "abc" was never
                 deleted when the myostr stream was destroyed. This
                 problem has been corrected. Note that the Class Library
                 strstream classes have always deleted the underlying
                 string.

              o  stringstream.str() can now be accessed after seekp(0)

                 The underlying string in a stringstream can now be
                 accessed properly after a seekp(0). For example, the
                 following program no longer causes a run-time core
                 dump.

                 #include <iostream>
                 #include <sstream>

                                                                      49

 






              int main()
              {
                 std::ostringstream out;
                 out << std::string("This is a test");
                 out.seekp(0);
                 std::cout << "out.str(): " << out.str() << std::endl;
                 return EXIT_SUCCESS;
              }

           o  <wchar.h> can be included before <fstream>

              Including <wchar.h> before <fstream> no longer causes
              compilation errors.

           o  std::ostrstream::freeze() no longer leaks memory

              The std::ostrstream::freeze() function no longer leaks
              memory when used in combination with an ostrstram
              object. If you declare an ostrstream object as
              std::ostrstream out, the memory to which output is
              written is dynamically allocated. Previously, calling
              freeze(false) incorrectly froze a stream, thereby
              preventing the deletion of allocated memory. This is no
              longer the case.

              The following program (which would have illustrated
              the memory leak when instrumented with third degree) no
              longer leaks memory.

















     50

 






                 #include <stdlib.h>
                 #ifndef __USE_STD_IOSTREAM
                 #define __USE_STD_IOSTREAM
                 #endif
                 #include <iostream>
                 #include <strstream>
                 void TestIt()
                 {
                    std::ostrstream out;
                    out << std::string("This is a test");
                    out.freeze(false);
                    char *s = out.str();
                    return;
                 }
                 int main()
                 {
                    for (int i = 0; i < 100; i++)
                        TestIt();
                    return EXIT_SUCCESS;
                 }

              o  Math overloads in <valarray> OK

                 Including <valarray> and then calling some of the math
                 routines (for example, abs()) with an int argument
                 might have produced an ambiguity error. This has been
                 corrected.

        4.11 Enhancements and Changes in Version 6.1

              The C++ Standard Library provided with this release
              defines a complete specification (with some differences)
              of the C++ International Standard. The library includes
              the ANSI locale and iostream libraries. Reference pages
              describing the Standard Library are provided; you can type
              man cxxlibstd_intro to access them.

              Tutorial programs illustrating functionality found in the
              Standard Library, including the locale, iostream, and STL
              classes shipped with this release are available in:

                   /usr/examples/cxx/*.cxx



                                                                      51

 






           You can compile and run these programs and use them as
           models for your own coding. The expected output for each
           program can be found in:

                /usr/examples/cxx/*.res

           Version 6.1 introduces the following major enhancements
           and changes. For detailed information, on the Compaq C++
           Standard Library, refer to  Using Compaq C++ for Tru64
           UNIX and Linux Alpha.

           o  Support for C++ International Standard iostream and
              locale

              The Version 6.1 kit contains detailed documentation in
              PostScript and PDF formats:

                 /usr/share/doclib/cplusplus/intzln.ps
                 /usr/share/doclib/cplusplus/intzln.pdf
                 /usr/share/doclib/cplusplus/locale.ps
                 /usr/share/doclib/cplusplus/locale.pdf

           o  Reference pages for the Standard Library. You can
              access them by typing man cxxlibstd_intro.

           o  Several new options (see The C++ Standard Library in
              Using Compaq C++ for Tru64 UNIX and Linux Alpha.)

           o  pre-ANSI/ANSI iostreams compatibility.

           o  Support for ANSI/pre-ANSI operator new().

           o  Support for global array new and delete.

           Additional changes include the following:

           o  Support for long long and unsigned long long types.

              The non-ANSI standard types long long and unsigned
              long long are now supported in the Standard Library
              iostreams as well as being valid types for numeric_
              limits specializations and as types for which
              destroy() specializations are provided. For example,
              you can now say:

              long long  l;
              cout << l << endl; // compiles without error

              Note that these types are not supported under -std
              strict_ansi or -std strict_ansi_errors compiler mode.

     52

 






                 long long and unsigned long long are also supported
                 in the iostream class library in the default compiler
                 mode.

              o  Common instantiation libraries no longer needed

                 Because Version 6.n uses compile time rather than link
                 time template instantiation, there is no use for common
                 instantiation libraries. No build_common_instantiation_library
                 script is supplied. See Using Templates in Using Compaq
                 C++ for Tru64 UNIX and Linux Alpha.

              o  Interface change for STL distance() function

                 Because the Version 6.1 compiler now supports partial
                 specialization of class templates, the interface to the
                 distance() algorithm has been updated to conform to
                 the latest C++ standard. This means that previously, if
                 you made a call to distance, the result was returned by
                 using a reference argument for the third argument:

                      // pre 6.1 the result was returned in d
                      distance(first,last,d);

                 Beginning with V6.1, the result is returned in the
                 return type:

                      d = distance(first,last); // 6.1

                 You must therefore change all your calls to distance().

              o  Specific changes to match the November C++ International
                 Standard:

                 o  iterator_traits::distance_type now iterator_
                    traits::difference_type

                    The name of the typedef inside the classes iterator_
                    traits and iterator that specifies the type of the
                    result when two iterators are subtracted has been
                    changed from distance_type to difference_type.

                 o  typedef name changes in iterator classes

                    The names of some of the typedefs in the reverse_
                    iterator and reverse_bidirectional_iterator classes
                    have changed as follows:

                       iter_type is now iterator_type
                       reference_type is now reference

                                                                      53

 






                    pointer_type is now pointer
                    distance_type is now difference_type

              o  slice/gslice classes member function length() name
                 change

                 The member function length() in the slice and
                 gslice classes has changed its name to size().

              o  has_denorm data member of the numeric_limits class
                 changed The has_denorm data member of the numeric_
                 limits class, <limits>, has been updated. has_
                 denorm is changed from type bool to an enum type,
                 float_denorm_style, to reflect that support for
                 denormalized values might not be detectable at
                 compile time. The float_denorm_style type looks
                 like this:

                       namespace std {
                           enum float_denorm_style {
                               denorm_indeterminate = -1;
                               denorm_absent = 0;
                               denorm_present = 1;
                           };
                       }

                 The values representing the presence or absence of
                 denorms are as follows:

                 denorm_indeterminate: cannot determine if type supports
                                       denormalized at compile time
                 denorm_absent:        the type does not support denormalized values
                 denorm_present:       the type supports denormalized values

              o  Default allocator value for map and multimap has
                 changed

                 The default value for the template argument
                 Allocator in map and multimap has changed from
                 allocator<T> to allocator<pair<const Key, T> >.

           o  Some Standard Library ambiguities corrected

              The Standard Library vector, deque and list containers
              no longer generate ambiguities when using their
              constructors or insert member functions. However, if
              you declare a basic_string of int, you might encounter
              ambiguities in the constructors, append, assign,

     54

 






                 insert, and replace member functions. For example if
                 you write:

                 #include <stdlib.h>
                 #include <string>
                 int main() {
                     basic_string<int> si (5,0);
                     return EXIT_SUCCESS;
                 }

                 A compilation error results from the overload
                 resolution between integral and iterator types. The
                 constructors involved are:

                   // construct n elements and initialize with value
                   basic_string(size_type n, charT c,
                                const Allocator& a = Allocator());

                   // construct a vector using iterator ranges
                   template<class InputIterator>
                   basic_string(InputIterator begin, InputIterator end,
                                const Allocator& a = Allocator());

                 The compiler matches on the constructor basic_
                 string(InputIterator begin, InputIterator end, ...)
                 The reason is that size_type a size_t is an unsigned
                 long on Compaq C++. So you have:

                     basic_string(unsigned long, int, ...)  vs.
                     basic_string(int, int,...)

                 The second constructor is the better match, but it is
                 not what we want, because we are not constructing with
                 iterator ranges.

                 The workaround is to avoid matching on iterator types
                 by casting integral arguments. So for example, the
                 previous program would compile correctly if the size
                 argument were cast to a (size_t):

                 #include <stdlib.h>
                 #include <string>
                 int main() {
                     basic_string<int> si ((size_t)5,0);
                     return EXIT_SUCCESS;
                 }

                                                                      55

 






     4.12 Problems Corrected in Version 6.1

           This section describes library problems corrected in
           Version 6.1.

           o  STL map containers are now accessible in multithreaded
              environments

              Erasing elements from two STL map containers in
              a multithreaded environment no longer causes a
              segmentation fault. With previous versions, the problem
              was caused by an incorrect locking mechanism in an
              implementation class used when a map is being "erased".

              To correct the original problem reported against the
              STL map class, we reworked map's entire underlying
              implementation class. The underlying implementation
              class is found in the <tree> header. This class has
              been modified so that it no longer contains static data
              members.

           o  Standard Library IOStream cerr.flush() no longer hangs
              in multithreaded environments

              Applications making use of the Standard Library
              IOStream cerr.flush() function in combination with
              other I/O related activities in a multithreaded
              environment no longer experience hangs in their
              executing code.

           o  Piping standard output or standard error to a file
              no longer loses output when using Standard Library
              IOStreams

              The symptoms of this Standard Library bug varied.
              One noticeable effect could be seen when executing a
              program using Standard Library IOStreams which inserted
              items to cout and then piped this output along with
              other output to a file.

              For example, if a program inserted into cout as
              follows:



     56

 






                 #define __USE_STD_IOSTREAM
                 #include <stdlib.h>
                 #include <iostream>
                 int main() {
                   cout << "Hello from C++" << endl;
                   return EXIT_SUCCESS
                 }

                 And if a script, d.sh executed the above program and
                 made use of a command that output to Standard Error
                 like this:

                 a.out
                 ls -X

                 And if you piped both Standard Output and Standard
                 Error to a file like this:

                 d.sh >& testlog

                 The output to Standard Output was lost. The testlog
                 would contain:

                 + ls -X
                 ls: illegal option -- X
                 usage: ls [ -1ACFLRabcdfgilmnopqrstux ]  [files]

                 Rather than:

                 Hello from C++
                 + ls -X
                 ls: illegal option -- X
                 usage: ls [ -1ACFLRabcdfgilmnopqrstux ]  [files]

                 This problem has been corrected.










                                                                      57
