GETSID(2) System Calls Manual GETSID(2)

getsidget process session

Standard C Library (libc, -lc)

#include <unistd.h>

pid_t
getsid(pid_t pid);

The session ID of the process identified by pid is returned by (). If pid is zero, getsid() returns the session ID of the current process.

Upon successful completion, the function getsid() returns the session ID of the specified process; otherwise, it returns a value of -1 and sets errno to indicate an error.

The getsid() system call will fail if:

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

Note that an implementation may restrict this function call to processes within the same session ID as the calling process.

getpgid(2), getpgrp(2), setpgid(2), setsid(2), termios(4)

The getsid() function call appeared in FreeBSD 3.0. The getsid() function call is derived from its usage in AT&T System V UNIX.

August 19, 1997 macOS 14.4