getsid() — Get process group ID of session leader

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 getsid(pid_t pid);

General description

The getsid() function obtains the process group ID of the process that is the session leader of the process specified by pid. If pid is 0, the system uses the PID of the process calling getsid().

Returned value

If successful, getsid() returns the process group ID of the session leader of the specified process.

If unsuccessful, getsid() returns (pid_t)-1 and sets errno to one of the following values:
Error Code
Description
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.

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