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<HTML><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><!-- Created on September, 12 2004 by texi2html 1.64 --><!-- Written by: Lionel Cons <Lionel.Cons@cern.ch> (original author) Karl Berry <karl@freefriends.org> Olaf Bachmann <obachman@mathematik.uni-kl.de> and many others.Maintained by: Olaf Bachmann <obachman@mathematik.uni-kl.de>Send bugs and suggestions to <texi2html@mathematik.uni-kl.de> --><HEAD><TITLE>Autoconf, Automake, and Libtool: Primitive macros to aid in building macros</TITLE><META NAME="description" CONTENT="Autoconf, Automake, and Libtool: Primitive macros to aid in building macros"><META NAME="keywords" CONTENT="Autoconf, Automake, and Libtool: Primitive macros to aid in building macros"><META NAME="resource-type" CONTENT="document"><META NAME="distribution" CONTENT="global"><META NAME="Generator" CONTENT="texi2html 1.64"><script language="Javascript"><!-- // Check the browser version. function checkVersion() { if (navigator.appVersion.charAt(0)>=3) return true; 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Autoconf extensively uses <CODE>m4</CODE>to perform the translation of <TT>`configure.in'</TT> to <TT>`configure'</TT>.Thus, it is necessary to understand implementation details such asM4's quoting rules in order to write Autoconf macros (<A HREF="autobook_191.html#SEC191">21. M4</A>).</P><P>Another aspect of macro writing which is extremely hard to get right iswriting portable Bourne shell scripts (see section <A HREF="autobook_208.html#SEC208">22. Writing Portable Bourne Shell</A>). Writing portable software, be it in Bourne shell or C++, issomething that can only be mastered with years of experience--andexposure to many different kinds of machines! Rather than expect allmacro writers to acquire this experience, it makes sense for Autoconf tobecome a `knowledge base' for this experience.</P><P>With this in mind, one future direction for Autoconf will be to providea library of low-level macros to assist in writing new macros. By way ofhypothetical example, consider the benefit of using a macro named<CODE>AC_FOREACH</CODE> instead of needing to learn the hard way that somevendor's implementation of Bourne shell has a broken <CODE>for</CODE> loopconstruct. This idea will be explored in future versions of Autoconf.</P><P>When migrating existing packages to the GNU Autotools, which is the topicof the next chapter, it is worth remember these guidelines for bestpractices as you write the necessary tests to make those packagesportable.</P><P><A NAME="Migrating Existing Packages"></A></TR></TABLE><BR> <FONT SIZE="-1">This document was generatedby <I>Gary V. Vaughan</I> on <I>September, 12 2004</I>using <A HREF="http://www.mathematik.uni-kl.de/~obachman/Texi2html"><I>texi2html</I></A></BODY></HTML>⌨️ 快捷键说明
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