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 return 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 various 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), in-
place(3am), ordchr(3am), readdir(3am), readfile(3am), revoutput(3am),
rwarray(3am), time(3am).
fork(2), wait(2), waitpid(2).
AUTHOR
Arnold Robbins, arnold@skeeve.com.
COPYING PERMISSIONS
Copyright (C) 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 distributed under the terms of a
permission notice identical to this one.
Permission is granted to copy and distribute translations of this man-
ual page into another language, under the above conditions for modified
versions, except that this permission notice may be stated in a trans-
lation approved by the Foundation.
Free Software Foundation Feb 02 2018 FORK(3am)