
       TimingLine  *ttv_AddHold(char  *input, char *output, double delay, char
       *dir);

DDEESSCCRRIIPPTTIIOONN
       Creates a hold constraint line between a data pin and a clock pin.

AARRGGUUMMEENNTTSS
       iinnppuutt         Data pin

       oouuttppuutt        Clock pin

       ddeellaayy         Nominal constraint value associated with the line

       ddiirr           Transitions on the data and clock pins: _u_u for input ris-
                     ing/output rising, _u_d for input rising/output falling, _d_d
                     for input falling/output  falling,  _d_u  for  input  fall-
                     ing/output rising.

