man/pthread_atfork.3

   1 .\" Copyright (c) 2004 Apple Computer, Inc.
   2 .\"
   3 .Dd August 12, 2004
   4 .Dt PTHREAD_ATFORK 3
   5 .Os
   6 .Sh NAME
   7 .Nm pthread_atfork
   8 .Nd register handlers to be called before and after
   9 .Fn fork
  10 .Sh SYNOPSIS
  11 .Fd #include <pthread.h>
  12 .Ft int
  13 .Fn pthread_atfork "void (*prepare)(void)" "void (*parent)(void)" "void (*child)(void)"
  14 .Sh DESCRIPTION
  15 The
  16 .Fn pthread_atfork
  17 function is used to register functions to be called before and after
  18 .Fn fork .
  19 The
  20 .Fa prepare
  21 handler is called before
  22 .Fn fork ,
  23 while the
  24 .Fa parent
  25 and
  26 .Fa child
  27 handlers are called after
  28 .Fn fork
  29 in the parent and child process respectively.
  30 The
  31 .Fa prepare
  32 handlers are called in reverse order of their registration, while
  33 .Fa parent
  34 and
  35 .Fa child
  36 handlers are called in the order in which they were registered.
  37 Any of the handlers may be NULL.
  38 .Pp
  39 .Em Important :
  40 only async-signal-safe functions are allowed on the child side of
  41 .Fn fork .
  42 See
  43 .Xr sigaction 2
  44 for details.
  45 .Sh RETURN VALUES
  46 If successful, the
  47 .Fn pthread_atfork
  48 function will return zero; otherwise an error number will be returned to
  49 indicate the error.
  50 .Sh ERRORS
  51 .Fn pthread_atfork
  52 will fail if:
  53 .Bl -tag -width Er
  54 .It Bq Er ENOMEM
  55 The system lacked the necessary resources to add another handler to the list.
  56 .El
  57 .Sh SEE ALSO
  58 .Xr fork 2
  59 .Sh STANDARDS
  60 .Fn pthread_atfork
  61 conforms to
  62 .St -p1003.1-96 .