man2/getsid.2

   1 .\" Copyright (C) 1996 Andries Brouwer (aeb@cwi.nl)
   2 .\"
   3 .\" This is free documentation; you can redistribute it and/or
   4 .\" modify it under the terms of the GNU General Public License as
   5 .\" published by the Free Software Foundation; either version 2 of
   6 .\" the License, or (at your option) any later version.
   7 .\"
   8 .\" The GNU General Public License's references to "object code"
   9 .\" and "executables" are to be interpreted as the output of any
  10 .\" document formatting or typesetting system, including
  11 .\" intermediate and printed output.
  12 .\"
  13 .\" This manual is distributed in the hope that it will be useful,
  14 .\" but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 .\" GNU General Public License for more details.
  17 .\"
  18 .\" You should have received a copy of the GNU General Public
  19 .\" License along with this manual; if not, write to the Free
  20 .\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
  21 .\" USA.
  22 .\"
  23 .\" Modified Thu Oct 31 14:18:40 1996 by Eric S. Raymond <esr@y\thyrsus.com>
  24 .\" Modified 2001-12-17, aeb
  25 .TH GETSID 2 2007-07-26 "Linux" "Linux Programmer's Manual"
  26 .SH NAME
  27 getsid \- get session ID
  28 .SH SYNOPSIS
  29 .B #include <unistd.h>
  30 .sp
  31 .BI "pid_t getsid(pid_t" " pid" );
  32 .sp
  33 .in -4n
  34 Feature Test Macro Requirements for glibc (see
  35 .BR feature_test_macros (7)):
  36 .in
  37 .sp
  38 .BR getsid ():
  39 _XOPEN_SOURCE\ >=\ 500
  40 .SH DESCRIPTION
  41 .I getsid(0)
  42 returns the session ID of the calling process.
  43 .I getsid(p)
  44 returns the session ID of the process with process ID
  45 .IR p .
  46 (The session ID of a process is the process group ID of the
  47 session leader.)
  48 .SH RETURN VALUE
  49 On success, a session ID is returned.
  50 On error, \fI(pid_t)\ \-1\fP will be returned, and
  51 .I errno
  52 is set appropriately.
  53 .SH ERRORS
  54 .TP
  55 .B EPERM
  56 A process with process ID
  57 .I p
  58 exists, but it is not in the same session as the current process,
  59 and the implementation considers this an error.
  60 .TP
  61 .B ESRCH
  62 No process with process ID
  63 .I p
  64 was found.
  65 .SH "CONFORMING TO"
  66 SVr4, POSIX.1-2001.
  67 .SH NOTES
  68 Linux does not return
  69 .BR EPERM .
  70 .LP
  71 Linux has this system call since Linux 1.3.44.
  72 There is libc support since libc 5.2.19.
  73 .SH "SEE ALSO"
  74 .BR getpgid (2),
  75 .BR setsid (2),
  76 .BR credentials (7)