wisejohn
/
buildtool


			
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<a name="libdep-Plugin"></a>
<div class="header">
<p>
Up: <a href="Plugins.html#Plugins" accesskey="u" rel="up">Plugins</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="LD-Index.html#LD-Index" title="Index" rel="index">Index</a>]</p>
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<hr>
<a name="Static-Library-Dependencies-Plugin"></a>
<h3 class="section">4.1 Static Library Dependencies Plugin</h3>
<a name="index-static-library-dependencies"></a>
<p>Originally, static libraries were contained in an archive file consisting
just of a collection of relocatable object files.  Later they evolved to
optionally include a symbol table, to assist in finding the needed objects
within a library.  There their evolution ended, and dynamic libraries
rose to ascendance.
</p>
<p>One useful feature of dynamic libraries was that, more than just collecting
multiple objects into a single file, they also included a list of their
dependencies, such that one could specify just the name of a single dynamic
library at link time, and all of its dependencies would be implicitly
referenced as well.  But static libraries lacked this feature, so if a
link invocation was switched from using dynamic libraries to static
libraries, the link command would usually fail unless it was rewritten to
explicitly list the dependencies of the static library.
</p>
<p>The GNU <code>ar</code> utility now supports a <samp>--record-libdeps</samp> option
to embed dependency lists into static libraries as well, and the <samp>libdep</samp>
plugin may be used to read this dependency information at link time.  The
dependency information is stored as a single string, carrying <samp>-l</samp>
and <samp>-L</samp> arguments as they would normally appear in a linker
command line.  As such, the information can be written with any text
utility and stored into any archive, even if GNU <code>ar</code> is not
being used to create the archive.  The information is stored in an
archive member named &lsquo;<samp>__.LIBDEP</samp>&rsquo;.
</p>
<p>For example, given a library <samp>libssl.a</samp> that depends on another
library <samp>libcrypto.a</samp> which may be found in <samp>/usr/local/lib</samp>,
the &lsquo;<samp>__.LIBDEP</samp>&rsquo; member of <samp>libssl.a</samp> would contain
</p>
<div class="smallexample">
<pre class="smallexample">-L/usr/local/lib -lcrypto
</pre></div>

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Up: <a href="Plugins.html#Plugins" accesskey="u" rel="up">Plugins</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="LD-Index.html#LD-Index" title="Index" rel="index">Index</a>]</p>
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