man2/getsid.2

   1 .\" Copyright (C) 1996 Andries Brouwer (aeb@cwi.nl)
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  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 2001-12-17 "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 .SH DESCRIPTION
  33 .I getsid(0)
  34 returns the session ID of the calling process.
  35 .I getsid(p)
  36 returns the session ID of the process with process ID
  37 .IR p .
  38 (The session ID of a process is the process group ID of the
  39 session leader.)
  40 .SH RETURN VALUE
  41 On success, a session ID is returned.
  42 On error, (pid_t) \-1 will be returned, and
  43 .I errno
  44 is set appropriately.
  45 .SH ERRORS
  46 .TP
  47 .B EPERM
  48 A process with process ID
  49 .I p
  50 exists, but it is not in the same session as the current process,
  51 and the implementation considers this an error.
  52 .TP
  53 .B ESRCH
  54 No process with process ID
  55 .I p
  56 was found.
  57 .SH "CONFORMING TO"
  58 SVr4, POSIX.1-2001.
  59 .SH NOTES
  60 Linux does not return EPERM.
  61 .LP
  62 Linux has this system call since Linux 1.3.44.
  63 There is libc support since libc 5.2.19.
  64 .LP
  65 To get the prototype under glibc, define both _XOPEN_SOURCE and
  66 _XOPEN_SOURCE_EXTENDED, or use "#define _XOPEN_SOURCE \fIn\fP"
  67 for some integer \fIn\fP larger than or equal to 500.
  68 .SH "SEE ALSO"
  69 .BR getpgid (2),
  70 .BR setsid (2),
  71 .BR credentials (7),
  72 .BR feature_test_macros (7)