Manual Pages  — GETPGRP

getpgrp – get process group

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES COMPATIBILITY ERRORS SEE ALSO STANDARDS HISTORY

Standard C Library (libc, -lc)

#include <unistd.h>

pid_t
getpgrp(void);

pid_t
getpgid(pid_t pid);

The getpgrp() system call always succeeds. Upon successful completion, the getpgid() system call returns the process group of the specified process; otherwise, it returns a value of -1 and sets errno to indicate the error.

This version of getpgrp() differs from past Berkeley versions by not taking a pid_t pid argument. This incompatibility is required by IEEE Std 1003.1-90 ("POSIX.1").

From the IEEE Std 1003.1-90 ("POSIX.1") Rationale:

BSD 4.3 provides a getpgrp() system call that returns the process group ID for a specified process. Although this function is used to support job control, all known job-control shells always specify the calling process with this function. Thus, the simpler AT&T V getpgrp() suffices, and the added complexity of the BSD 4.3 getpgrp() has been omitted from POSIX.1. The old functionality is available from the getpgid() system call.

The getpgid() system call will succeed unless:

[ESRCH]
	there is no process whose process ID equals pid

The getpgrp() system call is expected to conform to IEEE Std 1003.1-90 ("POSIX.1").

The getpgrp() system call appeared in BSD 4.0 . The getpgid() system call is derived from its usage in AT&T V.4 .