getsid (2)

Leading comments

Copyright (C) 1996 Andries Brouwer (aeb@cwi.nl)
and Copyright (C) 2016 Michael Kerrisk <mtk.manpages@gmail.com>

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(The comments found at the beginning of the groff file "man2/getsid.2".)

NAME

getsid - get session ID

SYNOPSIS

#include <unistd.h>

pid_t getsid(pid_t pid);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

getsid():

_XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
|| /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L

DESCRIPTION

getsid(0) returns the session ID of the calling process. getsid(p) returns the session ID of the process with process ID p. (The session ID of a process is the process group ID of the session leader.)

RETURN VALUE

On success, a session ID is returned. On error, (pid_t) -1 will be returned, and errno is set appropriately.

ERRORS

EPERM

A process with process ID p exists, but it is not in the same session as the calling process, and the implementation considers this an error.

ESRCH

No process with process ID p was found.

VERSIONS

This system call is available on Linux since version 2.0.

CONFORMING TO

POSIX.1-2001, POSIX.1-2008, SVr4.

NOTES

Linux does not return EPERM.

SEE ALSO

getpgid(2), setsid(2), credentials(7)

COLOPHON

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