This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding Linux
manual page for details of Linux behavior), or the interface may not be
implemented on Linux.
getsid — get the process group ID of a session leader
pid_t getsid(pid_t pid);
The getsid() function shall obtain the process group ID of the process
that is the session leader of the process specified by pid. If
pid is (pid_t)0, it specifies the calling process.
Upon successful completion, getsid() shall return the process group ID of
the session leader of the specified process. Otherwise, it shall return -1 and
set errno to indicate the error.
The getsid() function shall fail if:
- The process specified by pid is not in the same session as the
calling process, and the implementation does not allow access to the
process group ID of the session leader of that process from the calling
- There is no process with a process ID equal to pid.
The following sections are informative.
exec, fork(), getpid(),
getpgid(), setpgid(), setsid()
The Base Definitions volume of POSIX.1‐2017,
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1-2017, Standard for Information Technology -- Portable Operating
System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018
Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear in this page
are most likely to have been introduced during the conversion of the source
files to man page format. To report such errors, see