100 lines
2.6 KiB
Plaintext
100 lines
2.6 KiB
Plaintext
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.TH FORK 3am "Feb 02 2018" "Free Software Foundation" "GNU Awk Extension Modules"
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.SH NAME
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fork, wait, waitpid \- basic process management
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.SH SYNOPSIS
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.ft CW
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@load "fork"
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.sp
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pid = fork()
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.sp
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ret = waitpid(pid)
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.sp
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ret = wait();
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.ft R
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.SH DESCRIPTION
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The
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.I fork
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extension adds three functions, as follows.
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.TP
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.B fork()
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This function creates a new process. The return value is the zero
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in the child and the process-id number of the child in the parent,
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or \-1 upon error. In the latter case,
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.B ERRNO
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indicates the problem.
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In the child, \fBPROCINFO["pid"]\fP and \fBPROCINFO["ppid"]\fP
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are updated to reflect the correct values.
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.TP
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.B waitpid()
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This function takes a numeric argument, which is the process-id to
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wait for. The return value is that of the
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.IR waitpid (2)
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system call.
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.TP
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.B wait()
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This function waits for the first child to die.
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The return value is that of the
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.IR wait (2)
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system call.
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.\" .SH NOTES
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.SH BUGS
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There is no corresponding
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.B exec()
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function.
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.PP
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The interfaces could be enhanced to provide more facilities,
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including pulling out the various bits of the return status.
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.SH EXAMPLE
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.ft CW
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.nf
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@load "fork"
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\&...
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if ((pid = fork()) == 0)
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print "hello from the child"
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else
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print "hello from the parent"
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.fi
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.ft R
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.SH "SEE ALSO"
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.IR "GAWK: Effective AWK Programming" ,
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.IR filefuncs (3am),
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.IR fnmatch (3am),
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.IR inplace (3am),
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.IR ordchr (3am),
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.IR readdir (3am),
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.IR readfile (3am),
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.IR revoutput (3am),
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.IR rwarray (3am),
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.IR time (3am).
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.PP
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.IR fork (2),
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.IR wait (2),
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.IR waitpid (2).
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.SH AUTHOR
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Arnold Robbins,
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.BR arnold@skeeve.com .
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.SH COPYING PERMISSIONS
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Copyright \(co 2012, 2013, 2018,
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Free Software Foundation, Inc.
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.PP
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Permission is granted to make and distribute verbatim copies of
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this manual page provided the copyright notice and this permission
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notice are preserved on all copies.
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.ig
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Permission is granted to process this file through troff and print the
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results, provided the printed document carries copying permission
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notice identical to this one except for the removal of this paragraph
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(this paragraph not being relevant to the printed manual page).
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..
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.PP
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Permission is granted to copy and distribute modified versions of this
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manual page under the conditions for verbatim copying, provided that
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the entire resulting derived work is distributed under the terms of a
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permission notice identical to this one.
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.PP
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Permission is granted to copy and distribute translations of this
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manual page into another language, under the above conditions for
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modified versions, except that this permission notice may be stated in
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a translation approved by the Foundation.
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.\" vim: set filetype=nroff :
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