man > FORK(3am)

FORK(3am)                             GNU Awk Extension Modules                            FORK(3am)

NAME
       fork, wait, waitpid - basic process management

SYNOPSIS
       @load "fork"

       pid = fork()

       ret = waitpid(pid)

       ret = wait();

DESCRIPTION
       The fork extension adds three functions, as follows.

       fork() This function creates a new process. The return value is the zero in the child and the
              process-id  number  of  the child in the parent, or -1 upon error. In the latter case,
              ERRNO indicates the problem.  In the child, PROCINFO["pid"] and  PROCINFO["ppid"]  are
              updated to reflect the correct values.

       waitpid()
              This  function  takes a numeric argument, which is the process-id to wait for. The re‐
              turn value is that of the waitpid(2) system call.

       wait() This function waits for the first child to die.  The  return  value  is  that  of  the
              wait(2) system call.

BUGS
       There is no corresponding exec() function.

       The  interfaces could be enhanced to provide more facilities, including pulling out the vari‐
       ous bits of the return status.

EXAMPLE
       @load "fork"
       ...
       if ((pid = fork()) == 0)
           print "hello from the child"
       else
           print "hello from the parent"

SEE ALSO
       GAWK: Effective AWK Programming,  filefuncs(3am),  fnmatch(3am),  inplace(3am),  ordchr(3am),
       readdir(3am), readfile(3am), revoutput(3am), rwarray(3am), time(3am).

       fork(2), wait(2), waitpid(2).

AUTHOR
       Arnold Robbins, arnold AT skeeve.com.

COPYING PERMISSIONS
       Copyright © 2012, 2013, 2018, Free Software Foundation, Inc.

       Permission is granted to make and distribute verbatim copies of this manual page provided the
       copyright notice and this permission notice are preserved on all copies.

       Permission  is granted to copy and distribute modified versions of this manual page under the
       conditions for verbatim copying, provided that the entire resulting derived work is  distrib‐
       uted under the terms of a permission notice identical to this one.

       Permission  is  granted  to copy and distribute translations of this manual page into another
       language, under the above conditions for modified versions, except that this  permission  no‐
       tice may be stated in a translation approved by the Foundation.

Free Software Foundation                     Feb 02 2018                                   FORK(3am)