VMS Help CC, Run-time functions, setgid  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Implemented for program portability and serves no function.  It
  returns 0 (to indicate success).

  Syntax:

       #include <unistd.h>

       _DECC_V4_SOURCE defined:

       int setgid(__gid_t group_number);

       _DECC_V4_SOURCE not defined:

       gid_t setgid(gid_t group_number);