FORK
Section: GNU Awk Extension Modules (3am)
Updated: Feb 02 2018
Page Index
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),
inplace(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
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Free Software Foundation, Inc.
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