NAME

       getsid - get session ID

SYNOPSIS

       #include <sys/types.h>
       #include <unistd.h>

       pid_t getsid(pid_t pid);

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

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

DESCRIPTION

       getsid(0)  returns the session ID of the calling process.  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.

RETURN VALUE

       On success, a session ID is returned.  On error, (pid_t) -1 will be returned, and errno is
       set appropriately.

ERRORS

       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.

VERSIONS

       This system call is available on Linux since version 2.0.

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008, SVr4.

NOTES

       Linux does not return EPERM.

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

SEE ALSO

       getpgid(2), setsid(2), credentials(7)

COLOPHON

       This  page  is  part of release 4.15 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at https://www.kernel.org/doc/man-pages/.