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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!-- but may not be published or retransmitted without explicit permission.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 21:47:45 2005 by faqproc version 2.7 --><!-- from source file pointers.sgml dated Wed Dec 21 13:07:10 2005 --><!-- corresponding to FAQ list version 4.0 --><html><!-- Mirrored from c-faq.com/ptrs/passbyref.html by HTTrack Website Copier/3.x [XR&CO'2008], Sat, 14 Mar 2009 07:58:47 GMT --><head><meta name=GENERATOR content="faqproc"><title>Question 4.11</title><link href="refconst.html" rev=precedes><link href="funccall.html" rel=precedes><link href="index.html" rev=subdocument></head><body bgcolor="#ffffff"><a href="refconst.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="funccall.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 4.11</h1><p><font face=Helvetica size=8 color=blue><b>Q:</b></font>Does C even have ``pass by reference''?</p><p><hr><p><font face=Helvetica size=8 color=blue><b>A:</b></font>Not really.</p><p>Strictly speaking, C always uses pass by value.You can simulate pass by reference yourself,by defining functions which accept pointersand then using the <TT>&</TT> operator when calling,andthecompiler willessentiallysimulate itfor you when you pass an array to a function(by passing a pointer instead,see question <a href="../aryptr/aryptrparam.html">6.4</a> et al.).</p><p>Another way of looking at it is thatif an parameter has type, say, <TT>int *</TT>then an integer is being passed by referenceand a pointer to an integer is being passed by value.</p><p>Fundamentally,C has nothing trulyequivalent to formal pass by referenceor C++ reference parameters.(On the other hand,function-like preprocessor macroscanprovide a form of ``pass by name''.)</p><p>See alsoquestions <a href="passptrinit.html">4.8</a>, <a href="../malloc/mymallocretp.html">7.9</a>, <a href="../stdio/fopenfp.html">12.27</a>, and <a href="../misc/multretval.html">20.1</a>.</p><p>Additional links:A<a href="passbyref2.html">message of mine</a>further explaining how a function can modify a caller's passed array.</p><p>References:K&R1 Sec. 1.8 pp. 24-5, Sec. 5.2 pp. 91-3<br>K&R2 Sec. 1.8 pp. 27-8, Sec. 5.2 pp. 95-7<br>ISO Sec. 6.3.2.2<br>H&S Sec. 9.5 pp. 273-4<br></p><!-- aend --><p><hr><a href="refconst.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="funccall.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/ptrs/passbyref.html by HTTrack Website Copier/3.x [XR&CO'2008], Sat, 14 Mar 2009 07:58:48 GMT --></html>⌨️ 快捷键说明
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