Changes in / [6af4dab:2ff3ada]

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• chapter05/libstdc++.xml (modified) (1 diff)

chapter05/libstdc++.xml

@@ -93 +93 @@
         <term><parameter>--with-gxx-include-dir=/tools/$LFS_TGT/include/c++/&gcc-version;</parameter></term>
         <listitem>
-          <para>This is the location where the C++ compiler should search for the
-          standard include files. In a normal build, this information
+          <para>This specifies the installation directory for include files.
+          Because libstdc++ is the standard C++ library for LFS, this
+          directory should match the location where the C++ compiler
+          (<command>$LFS_TGT-g++</command>) would search for the
+          standard C++ include files. In a normal build, this information
           is automatically passed to the libstdc++ <command>configure</command>
           options from the top level directory. In our case, this information
-          must be explicitly given.</para>
+          must be explicitly given.
+          The C++ compiler will prepend the sysroot path
+          <filename class="directory">$LFS</filename> (specified building
+          GCC pass 1) to the include file search path, so it will actually
+          search in
+          <filename class="directory">$LFS/tools/$LFS_TGT/include/c++/&gcc-version;</filename>.
+          The combination of the <parameter>DESTDIR</parameter>
+          variable (in the <command>make install</command> command below)
+          and this switch ensures to install the headers there.</para>
         </listitem>
       </varlistentry>