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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: Using Configuration Names</TITLE><META NAME="description" CONTENT="Autoconf, Automake, and Libtool: Using Configuration Names"><META NAME="keywords" CONTENT="Autoconf, Automake, and Libtool: Using Configuration Names"><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; if (navigator.appVersion.charAt(0)>=4) return true; 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This may be necessary if certain code must be compileddifferently based on something which can not be tested using a standardAutoconf feature test. For instance, the <CODE>expect</CODE> package needs tofind information about the system's <SAMP>`tty'</SAMP> implementation; thiscan't reliably be done when cross compiling without examining theparticular configuration name.</P><P>It is normally better to test for particular features, rather than totest for a particular system type. This is because as Unix and otheroperating systems evolve, different systems copy features from oneanother.</P><P>When there is no alternative to testing the configuration name in a<TT>`configure'</TT> script, it is best to define a macro which describesthe feature, rather than defining a macro which describes the particularsystem. This permits the same macro to be used on other systemswhich adopt the same feature (see section <A HREF="autobook_221.html#SEC221">23. Writing New Macros for Autoconf</A>).</P><P>Testing for a particular system is normally done using a case statementin the autoconf <TT>`configure.in'</TT> file. The <CODE>case</CODE> statementmight look something like the following, assuming that <SAMP>`host'</SAMP> is ashell variable holding a canonical configuration system--which will bethe case if <TT>`configure.in'</TT> uses the <SAMP>`AC_CANONICAL_HOST'</SAMP> or<SAMP>`AC_CANONICAL_SYSTEM'</SAMP> macros.</P><P><TABLE><tr><td> </td><td class=smallexample><FONT SIZE=-1><pre>case "${host}" ini[[3456]]86-*-linux-gnu*) do something ;;sparc*-sun-solaris2.[[56789]]*) do something ;;sparc*-sun-solaris*) do something ;;mips*-*-elf*) do something ;;esac</FONT></pre></td></tr></table></P><P>Note the doubled square brackets in this piece of code. These are usedto work around an ugly implementation detail of <CODE>autoconf</CODE>---ituses M4 under the hood. Without these extra brackets, the squarebrackets in the <CODE>case</CODE> statement would be swallowed by M4, andwould not appear in the resulting <TT>`configure'</TT>. This nasty detailis discussed at more length in <A HREF="autobook_191.html#SEC191">21. M4</A>.</P><P>It is particularly important to use <SAMP>`*'</SAMP> after the operating systemfield, in order to match the version number which will be generated by<TT>`config.guess'</TT>. In most cases you must be careful to match a rangeof processor types. For most processor families, a trailing <SAMP>`*'</SAMP>suffices, as in <SAMP>`mips*'</SAMP> above. For the i386 family, somethingalong the lines of <SAMP>`i[34567]86'</SAMP> suffices at present. For the m68kfamily, you will need something like <SAMP>`m68*'</SAMP>. Of course, if you donot need to match on the processor, it is simpler to just replace theentire field by a <SAMP>`*'</SAMP>, as in <SAMP>`*-*-irix*'</SAMP>.</P><P><A NAME="Introducing GNU Automake"></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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