bsd/man/man2/_exit.2

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  34 .\"     @(#)_exit.2     8.1 (Berkeley) 6/4/93
  35 .\"
  36 .Dd June 4, 1993
  37 .Dt EXIT 2
  38 .Os BSD 4
  39 .Sh NAME
  40 .Nm _exit
  41 .Nd terminate the calling process
  42 .Sh SYNOPSIS
  43 .Fd #include <unistd.h>
  44 .Ft void
  45 .Fo _exit
  46 .Fa "int status"
  47 .Fc
  48 .Sh DESCRIPTION
  49 The
  50 .Fn _exit
  51 function
  52 terminates a process, with the following consequences:
  53 .Bl -bullet
  54 .It
  55 All of the descriptors that were open in the calling process are closed.
  56 This may entail delays; for example, waiting for output to drain.
  57 A process in this state may not be killed, as it is already dying.
  58 .It
  59 If the parent process of the calling process has an outstanding
  60 .Xr wait
  61 call
  62 or catches the
  63 .Dv SIGCHLD
  64 signal,
  65 it is notified of the calling process's termination;
  66 the
  67 .Em status
  68 is set as defined by
  69 .Xr wait 2 .
  70 .It
  71 The parent process-ID of all of the calling process's existing child
  72 processes are set to 1; the initialization process
  73 (see the DEFINITIONS section of
  74 .Xr intro 2 )
  75 inherits each of these processes.
  76 .It
  77 If the termination of the process causes any process group
  78 to become orphaned (usually because the parents of all members
  79 of the group have now exited; see
  80 .Dq orphaned process group
  81 in
  82 .Xr intro 2 ) ,
  83 and if any member of the orphaned group is stopped,
  84 the
  85 .Dv SIGHUP
  86 signal and the
  87 .Dv SIGCONT
  88 signal are sent to all members of the newly-orphaned process group.
  89 .It
  90 If the process is a controlling process (see
  91 .Xr intro 2 ) ,
  92 the
  93 .Dv SIGHUP
  94 signal is sent to the foreground process group of the controlling terminal.
  95 All current access to the controlling terminal is revoked.
  96 .El
  97 .Pp
  98 Most C programs call the library routine
  99 .Xr exit 3 ,
 100 which flushes buffers, closes streams, unlinks temporary files, etc.,
 101 before
 102 calling
 103 .Fn _exit .
 104 .Sh RETURN VALUE
 105 .Fn _exit
 106 can never return.
 107 .Sh SEE ALSO
 108 .Xr fork 2 ,
 109 .Xr sigaction 2 ,
 110 .Xr wait 2 ,
 111 .Xr exit 3
 112 .Sh STANDARDS
 113 The
 114 .Nm _exit
 115 function is defined by
 116 .St -p1003.1-88 .