SETPGID(2) BSD System Calls Manual SETPGID(2)
setpgid, setpgrp -- set process group
setpgid(pid_t pid, pid_t pgrp);
setpgrp(pid_t pid, pid_t pgrp);
Setpgid() sets the process group of the specified process pid to the
specified pgrp. If pid is zero, then the call applies to the current
If the invoker is not the super-user, then the affected process must have
the same effective user-id as the invoker or be a descendant of the
Setpgid() returns 0 when the operation was successful. If the request
failed, -1 is returned and the global variable errno indicates the rea-
Setpgid() will fail and the process group will not be altered if:
[EACCES] The value of the pid argument matches the process ID
of a child process of the calling process, and the
child process has successfully executed one of the
[EPERM] The effective user ID of the requested process is dif-
ferent from that of the caller and the process is not
a descendant of the calling process.
[ESRCH] The value of the pid argument does not match the
process ID of the calling process or of a child
process of the calling process.
The setpgid() function conforms to IEEE Std 1003.1-1988 (``POSIX.1'').
Setpgrp() is identical to setpgid(), and is retained for calling conven-
tion compatibility with historical versions of BSD.
4th Berkeley Distribution June 4, 1993 4th Berkeley Distribution