getsid - get session ID

getsid() returns the session ID of the process with process ID pid. If pid is 0, getsid() returns the session ID of the calling process.

EPERM A process with process ID pid exists, but it is not in the same session as the calling process, and the implementation considers this an error. ESRCH No process with process ID pid was found.

POSIX.1-2001, SVr4. Linux 2.0.

Standard C library (libc, -lc)

getsid - get session ID

See credentials(7) for a description of sessions and session IDs.

On success, a session ID is returned. On error, (pid_t)-1 is returned, and errno is set to indicate the error.

getpgid(2), setsid(2), credentials(7) Linux man-pages 6.9.1 2024-05-02 getsid(2)

POSIX.1-2008.

#include<unistd.h>pid_tgetsid(pid_tpid); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): getsid(): _XOPEN_SOURCE >= 500 || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L

Linux does not return EPERM.