bsd/man/man2/getsid.2

   1 .\" Copyright (c) 1997 Peter Wemm <peter@FreeBSD.org>
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  24 .\" $FreeBSD: src/lib/libc/sys/getsid.2,v 1.3.2.5 2001/12/14 18:34:00 ru Exp $
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  26 .Dd August 19, 1997
  27 .Dt GETSID 2
  28 .Os
  29 .Sh NAME
  30 .Nm getsid
  31 .Nd get process session
  32 .Sh LIBRARY
  33 .Lb libc
  34 .Sh SYNOPSIS
  35 .In unistd.h
  36 .Ft pid_t
  37 .Fo getsid
  38 .Fa "pid_t pid"
  39 .Fc
  40 .Sh DESCRIPTION
  41 The session ID of the process identified by
  42 .Fa pid
  43 is returned by
  44 .Fn getsid .
  45 If
  46 .Fa pid
  47 is zero,
  48 .Fn getsid
  49 returns the session ID of the current process.
  50 .Sh RETURN VALUES
  51 Upon successful completion, the function
  52 .Fn getsid
  53 returns the session ID of
  54 the specified process; otherwise, it returns a value of -1 and
  55 sets errno to indicate an error.
  56 .Sh ERRORS
  57 The
  58 .Fn getsid
  59 system call will fail if:
  60 .Bl -tag -width Er
  61 .\" ==========
  62 .It Bq Er ESRCH
  63 There is no process with a process ID equal to
  64 .Fa pid .
  65 .El
  66 .Pp
  67 Note that an implementation may restrict this function call to
  68 processes within the same session ID as the calling process.
  69 .Sh SEE ALSO
  70 .Xr getpgid 2 ,
  71 .Xr getpgrp 2 ,
  72 .Xr setpgid 2 ,
  73 .Xr setsid 2 ,
  74 .Xr termios 4
  75 .Sh HISTORY
  76 The
  77 .Fn getsid
  78 function call appeared in
  79 .Fx 3.0 .
  80 The
  81 .Fn getsid
  82 function call is derived from its usage in
  83 .At V .