---
name: "getsid"
section: "3p"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/getsid/3p"
---

# getsid(3p)

get the process group ID of a session leader

## PROLOG

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.

## NAME

getsid — get the process group ID of a session leader

## SYNOPSIS

```
#include <unistd.h>
```

pid\_t getsid(pid\_t *pid*);

## DESCRIPTION

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.

## RETURN VALUE

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.

## ERRORS

The *getsid*() function shall fail if:

- **EPERM**

  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 process.

- **ESRCH**

  There is no process with a process ID equal to *pid*.

*The following sections are informative.*

## EXAMPLES

None.

## APPLICATION USAGE

None.

## RATIONALE

None.

## FUTURE DIRECTIONS

None.

## SEE ALSO

*exec*, *fork()*, *getpid()*, *getpgid()*, *setpgid()*, *setsid()*

The Base Definitions volume of POSIX.1‐2017, ***\<unistd.h\>***

## COPYRIGHT

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 https://www.kernel.org/doc/man-pages/reporting\_bugs.html .