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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!-- but may not be published or retransmitted without explicit permission.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 21:47:46 2005 by faqproc version 2.7 --><!-- from source file ansi.sgml dated Wed Aug 11 00:43:45 2004 --><!-- corresponding to FAQ list version 4.0 --><html><!-- Mirrored from c-faq.com/ansi/voidmain.html by HTTrack Website Copier/3.x [XR&CO'2008], Sat, 14 Mar 2009 07:58:55 GMT --><head><meta name=GENERATOR content="faqproc"><title>Question 11.12b</title><link href="maindecl.html" rev=precedes><link href="envp.html" rel=precedes><link href="index.html" rev=subdocument></head><body bgcolor="#ffffff"><a href="maindecl.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="envp.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 11.12b</h1><p><font face=Helvetica size=8 color=blue><b>Q:</b></font>Can I declare <TT>main</TT> as <TT>void</TT>,to shut off these annoying``main returns no value'' messages?</p><p><hr><p><font face=Helvetica size=8 color=blue><b>A:</b></font>No.<TT>main</TT> must be declared as returning an <TT>int</TT>,and astaking either zero or two arguments,of the appropriate types.If you're calling <TT>exit()</TT> but still getting warnings,you may have to insert a redundant <TT>return</TT> statement(or use some kindof ``not reached'' directive,if available).</p><p>Declaring a function as <TT>void</TT> does not merelyshut off or rearrangewarnings:it may also result in a differentfunction call/return sequence,incompatible with what the caller(in <TT>main</TT>'s case, the C run-time startup code)expects.That is,if the calling sequences for <TT>void</TT>-and <TT>int</TT>-valued functions differ,the startup code is going to be calling <TT>main</TT>usingspecifically the<TT>int</TT>-valued conventions,and if <TT>main</TT> has been improperly declared as <TT>void</TT>,it may notwork.(See also question <a href="../struct/retcrash.html">2.18</a>.)</p><p>(Note thatthis discussion of <TT>main</TT>pertains only to ``hosted'' implementations;none of it applies to ``freestanding'' implementations,which may not even have <TT>main</TT>.However,freestanding implementations are comparatively rare,and if you're using one,you probably know it.If you've never heard of the distinction,you're probably using a hosted implementation,and the above rules apply.)</p><p>Additional links:<a href="sd11.html" rel=subdocument>further reading</a></p><p>References:ISO Sec. 5.1.2.2.1, Sec. G.5.1<br>H&S Sec. 20.1 p. 416<br>CT&P Sec. 3.10 pp. 50-51<br></p><!-- aend --><p><hr><a href="maindecl.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="envp.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/ansi/voidmain.html by HTTrack Website Copier/3.x [XR&CO'2008], Sat, 14 Mar 2009 07:58:55 GMT --></html>⌨️ 快捷键说明
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