getpgid() — Get process group ID

Standards

Standards / Extensions	C or C++	Dependencies
XPG4.2 Single UNIX Specification, Version 3	both

Format

#define _XOPEN_SOURCE_EXTENDED 1
#include <unistd.h>

pid_t getpgid(pid_t pid);

General description

The getpgid() function returns the process group ID of the process whose process ID is equal to pid. If pid is 0, getpgid() returns the PID of the calling process.

Returned value

If successful, getpgid() returns a process group ID.

If unsuccessful, getpgid() returns (pid_t)-1 and sets errno to one of the following values:

Error Code: Description
EPERM: The process whose process ID is equal to pid is not the same session as the calling process, and the implementation does not allow to the process group ID of that process from the calling process.
ESRCH: There is no process with a process ID equal to pid.

getpgid() may fail if:

Error Code: Description
EINVAL: The value of the pid argument is not valid.

Related information

unistd.h
exec functions
fork() — Create a new process
getpgrp() — Get the process group ID
getsid() — Get process group ID of session leader
setregid() — Set real and effective group IDs
setsid() — Create session, set process group ID