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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!-- but may not be published or retransmitted without explicit permission.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 varargs.sgml dated Sun Nov 25 08:09:42 2001 --><!-- corresponding to FAQ list version 4.0 --><html><!-- Mirrored from c-faq.com/varargs/vprintf.html by HTTrack Website Copier/3.x [XR&CO'2008], Sat, 14 Mar 2009 07:59:00 GMT --><head><meta name=GENERATOR content="faqproc"><title>Question 15.5</title><link href="varargs1.html" rev=precedes><link href="vscanf.html" rel=precedes><link href="index.html" rev=subdocument></head><body bgcolor="#ffffff"><a href="varargs1.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="vscanf.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 15.5</h1><p><font face=Helvetica size=8 color=blue><b>Q:</b></font>How can I write a function that takes a format string and avariable number of arguments, like <TT>printf</TT>, and passes them to<TT>printf</TT> to do most of the work?</p><p><hr><p><font face=Helvetica size=8 color=blue><b>A:</b></font>Use <TT>vprintf</TT>, <TT>vfprintf</TT>,or <TT>vsprintf</TT>.These routines are like their counterparts<TT>printf</TT>, <TT>fprintf</TT>, and <TT>sprintf</TT>,except that instead of a variable-length argument list,they accept a single <TT>va_list</TT> pointer.</p><p>As an example,hereis an <TT>error</TT>function which prints an error message,preceded by the string ``error: '' and terminated with a newline:</p><pre>#include <stdio.h>#include <stdarg.h>void error(const char *fmt, ...){ va_list argp; fprintf(stderr, "error: "); va_start(argp, fmt); vfprintf(stderr, fmt, argp); va_end(argp); fprintf(stderr, "\n");}</pre><p>See also question <a href="oldvarargs.html">15.7</a>.</p><p>References:K&R2 Sec. 8.3 p. 174, Sec. B1.2 p. 245<br>ISO Secs. 7.9.6.7,7.9.6.8,7.9.6.9<br>H&S Sec. 15.12 pp. 379-80<br>PCS Sec. 11 pp. 186-7<br></p><!-- aend --><p><hr><a href="varargs1.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="vscanf.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/varargs/vprintf.html by HTTrack Website Copier/3.x [XR&CO'2008], Sat, 14 Mar 2009 07:59:00 GMT --></html>⌨️ 快捷键说明
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