getsid man page


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


#include <unistd.h>

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.

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.


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

The following sections are informative.

See Also

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

The Base Definitions volume of POSIX.1‐2008, <unistd.h>