---
name: "setpgrp"
section: "2freebsd"
platform: "linux"
package: "freebsd-manpages"
version: "12.2-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/setpgid/2freebsd"
---

# setpgrp(2freebsd)

set process group

Part of [setpgid(2freebsd)](/setpgid/2freebsd.md).

## NAME

**setpgid**, **setpgrp** – set process group

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<unistd.h\>**

*int*\

**setpgid**(*pid\_t pid*, *pid\_t pgrp*);

*int*\

**setpgrp**(*pid\_t pid*, *pid\_t pgrp*);

## DESCRIPTION

The **setpgid**() system call sets the process group of the specified process *pid* to the specified *pgrp*. If *pid* is zero, then the call applies to the current process. If *pgrp* is zero, then the process id of the process specified by *pid* is used instead.

If the affected process is not the invoking process, then it must be a child of the invoking process, it must not have performed an [exec(3)](/exec/3.md) operation, and both processes must be in the same session. The requested process group ID must already exist in the session of the caller, or it must be equal to the target process ID.

## RETURN VALUES

The **setpgid()** function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

## COMPATIBILITY

The **setpgrp**() system call is identical to **setpgid**(), and is retained for calling convention compatibility with historical versions of BSD.

## ERRORS

The **setpgid**() system call will fail and the process group will not be altered if:

- \[EINVAL\]

  The requested process group ID is not legal.

- \[ESRCH\]

  The requested process does not exist.

- \[ESRCH\]

  The target process is not the calling process or a child of the calling process.

- \[EACCES\]

  The requested process is a child of the calling process, but it has performed an [exec(3)](/exec/3.md) operation.

- \[EPERM\]

  The target process is a session leader.

- \[EPERM\]

  The requested process group ID is not in the session of the caller, and it is not equal to the process ID of the target process.

## SEE ALSO

[getpgrp(2)](/getpgrp/2.md)

## STANDARDS

The **setpgid**() system call is expected to conform to ISO/IEC 9945-1:1990 (“POSIX.1”).