fork, wait, waitpid - basic process management


   @load "fork"

   pid = fork()

   ret = waitpid(pid)

   ret = wait();


   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.

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

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


   There is no corresponding exec() function.

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


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


   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).


   Arnold Robbins,


   Copyright  2012, 2013, 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 distributed 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 notice may be stated  in
   a translation approved by the Foundation.

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