getsid(glossar.html) - phpMan

GETSID(2)                  Linux Programmer's Manual                 GETSID(2)
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/.
Linux                             2017-09-15                         GETSID(2)