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GETSID(2)                  Linux Programmer's Manual                 GETSID(2)

NAME
       getsid - get session ID
SYNOPSIS
       #include <unistd.h>
       pid_t getsid(pid_t pid);
   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
       getsid():
           _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
           || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
DESCRIPTION
       getsid(0)  returns  the  session  ID of the calling process.  getsid(p)
       returns the session ID of the process with process ID p.  (The  session
       ID of a process is the process group ID of the session leader.)
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 p 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 p was found.
VERSIONS
       This system call is available on Linux since version 2.0.
CONFORMING TO
       SVr4, POSIX.1-2001.
NOTES
       Linux does not return EPERM.
SEE ALSO
       getpgid(2), setsid(2), credentials(7)
COLOPHON
       This page is part of release 3.53 of the Linux  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux                             2010-09-26                         GETSID(2)