ultrix man page for setpgrp

setpgrp(2)							System Calls Manual							setpgrp(2)

Name
       setpgrp - set process group

Syntax
       setpgrp(pid, pgrp)
       int pid, pgrp;

Description
       The system call sets the process group of the specified process pid to the specified pgrp.  If pid is zero, the call applies to the current
       process.

       If the invoker is not the superuser, the affected process must either have the same effective user-id as the invoker or be a descendant	of
       the invoking process.

Return Values
       The  system  call  returns  zero (0) when the operation is successful.  If the request fails, -1 is returned, and the global variable errno
       indicates the reason.

Environment
       SYSTEM_FIVE

       When your program is compiled using the System V environment, is called without arguments and the new process group id is returned if  suc-
       cessful.

Diagnostics
       The system call fails and the process group is not altered, if one of the following occur:

       [EPERM]	      The  effective  user ID of the requested process is different from that of the caller and the process is not a descendent of
		      the calling process.

       [ESRCH]	      The requested process does not exist.

See Also
       getpgrp(2)

																	setpgrp(2)