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<!DOCTYPE HTML PUBLIC "-//W3O//DTD W3 HTML 2.0//EN"><!-- This collection of hypertext pages is Copyright 1995-2005 by Steve Summit. --><!-- Content from the book "C Programming FAQs: Frequently Asked Questions" --><!-- (Addison-Wesley, 1995, ISBN 0-201-84519-9) is made available here by --><!-- permission of the author and the publisher as a service to the community. --><!-- It is intended to complement the use of the published text --><!-- and is protected by international copyright laws. --><!-- The on-line content may be accessed freely for personal use --><!-- but may not be published or retransmitted without explicit permission. --><!-- --><!-- this page built Sat Dec 24 21:47:47 2005 by faqproc version 2.7 --><!-- from source file osdepproc.sgml dated Sat Feb 7 19:18:20 2004 --><!-- corresponding to FAQ list version 4.0 --><html><!-- Mirrored from c-faq.com/osdep/system.html by HTTrack Website Copier/3.x [XR&CO'2008], Sat, 14 Mar 2009 07:59:03 GMT --><head><meta name=GENERATOR content="faqproc"><title>Question 19.27</title><link href="accessloc0.html" rev=precedes><link href="system2.html" rel=precedes><link href="index.html" rev=subdocument></head><body bgcolor="#ffffff"><a href="accessloc0.html" rev=precedes><img src="../images/buttonleft.gif" alt="prev"></a><a href="index.html" rev=subdocument><img src="../images/buttonup.gif" alt="up"></a><a href="system2.html" rel=precedes><img src="../images/buttonright.gif" alt="next"></a> <a href="../index-2.html"><img src="../images/buttontop.gif" alt="top/contents"></a><a href="../search.html"><img src="../images/buttonsrch.gif" alt="search"></a><hr><p><!-- qbegin --><h1>comp.lang.c FAQ list<font color=blue>·</font><!-- qtag -->Question 19.27</h1><p><font face=Helvetica size=8 color=blue><b>Q:</b></font>How can I invokeanother program(a standalone executable,or an operating system command)from within a C program?</p><p><hr><p><font face=Helvetica size=8 color=blue><b>A:</b></font>Usethe library function<TT>system</TT>,which does exactly that.</p><p>Some systems also provide a family of <TT>spawn</TT>routines which accomplishapproximately the same thing.<TT>system</TT> is more ``portable''in that it is required under the ANSI C Standard,although the interpretation of the commandstring--itssyntax and the set of commandsaccepted--willobviously vary tremendously.</p><p>The<TT>system</TT>function``calls''a command in the manner of a subroutine,and controleventuallyreturns to the calling program.If you want to overlay the calling program with another program(that is,a ``chain'' operation)you'll need asystem-specific routine,such as the <TT>exec</TT> family on Unix.</p><p>Notethat <TT>system</TT>'s return valueisat bestthe command's exit status(although even that is not guaranteed),and usually has nothing to do with the output of the command.</p><p>See alsoquestions<a href="system2.html">19.28</a>and<a href="popen.html">19.30</a>.</p><p>References:K&R1 Sec. 7.9 p. 157<br>K&R2 Sec. 7.8.4 p. 167, Sec. B6 p. 253<br>ISO Sec. 7.10.4.5<br>H&S Sec. 19.2 p. 407<br>PCS Sec. 11 p. 179<br></p><!-- aend --><p><hr><a href="accessloc0.html" rev=precedes><img src="../images/buttonleft.gif" alt="prev"></a><a href="index.html" rev=subdocument><img src="../images/buttonup.gif" alt="up"></a><a href="system2.html" rel=precedes><img src="../images/buttonright.gif" alt="next"></a> <a href="../questions.html"><img src="../images/buttontop.gif" alt="contents"></a><a href="../search.html"><img src="../images/buttonsrch.gif" alt="search"></a><br><!-- lastfooter --><a href="../about.html">about this FAQ list</a> <a href="../eskimo.html">about eskimo</a> <a href="../search.html">search</a> <a href="../feedback.html">feedback</a> <a href="copyright.html">copyright</a><p>Hosted by<a href="http://www.eskimo.com/"><img src="../../www.eskimo.com/img/link/eskitiny.gif" alt="Eskimo North"></a></body><!-- Mirrored from c-faq.com/osdep/system.html by HTTrack Website Copier/3.x [XR&CO'2008], Sat, 14 Mar 2009 07:59:03 GMT --></html>⌨️ 快捷键说明
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