NAME

getsid - get session ID

LIBRARY

Standard C library (libc, -lc)

#include <unistd.h>
pid_t getsid(pid_t pid);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

    _XOPEN_SOURCE >= 500
        || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L

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.

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

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.

Linux does not return EPERM.

POSIX.1-2008.

POSIX.1-2001, SVr4. Linux 2.0.

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