precompiled header

[Philippe Elie]

Using precompiled header with gcc cvs is usefull, libstdc++
install two of them in ../..../bits/stdc++.h.gch under the
name O0g O2G the documentation speak about using
-include stdc++.h to get this precompiled header but

  - stdc++.h is not installed
  - manually installing it doesn't seem to work

documentation says:

--enable-libstdcxx-pch

     In 3.4 and later, tries to turn on the generation of stdc++.h.gch, 
a pre-compiled file including all the standard C++ includes. If enabled 
(as by default), and the compiler seems capable of passing the simple 
sanity checks thrown at it, try to build stdc++.h.gch as part of the 
make process. In addition, this generated file is used later on (by 
appending --include bits/stdc++.h to CXXFLAGS) when running the testsuite.


can someone clarify how it must works, especially how
-include bits/stdc++.h can match one of the precompiled
filename ?


regards,
Philippe Elie