Even closer this time.
The B.cpp file only has one line -- #include "B.h"
Instead of using the gch file generated by the g++ command in the make file.
I manually ran:
g++ -fPIC -O -O3 -DUSING_PCH -D_REENTRANT -I"/usr/local/include/boost"
-I"/usr/local/." -I"/opt/xerces-c-3.1.1/src" -x c++-header A/B.h.gch
A/B.h
Then, I compiled my own project with "-include A/B.h" in Eclipse, I got
cc1plus: warning: /opt/3rdPartyLib/src/A/B.h.gch not used because A/B.h.gch created with -gnone, but used with -gdwarf-2
Then, I recompiled the gch file with -gdwarf-2, and recompiled my project again, I got:
cc1plus: warning: /opt/3rdPartyLib/src/A/B.h.gch not used because
`_REENTRANT' is not defined
Then, I recompiled the gch file with -D_REENTRANT, and recompiled my
project again, I got:
cc1plus: warning: /opt/3rdPartyLib/src/A/B.h.gch not used because
`__NO_INLINE__' is defined
I just wonder whether there is a simple way to use a precompiled header....
Thanks in advance.
----- Original Message ----
From: Ian Lance Taylor <iant@xxxxxxxxxx>
To: Hei Chan <structurechart@xxxxxxxxx>
Cc: gcc-help@xxxxxxxxxxx
Sent: Wed, June 23, 2010 10:39:07 AM
Subject: Re: How to use precompiled header?
Hei Chan <structurechart@xxxxxxxxx> writes:
> I think that I am getting close:
>
> cc1plus: warning: /opt/3rdPartyLib/src/A/B.h.gch: not a PCH file
>
>
> B.h.gch is generated by the 3rd party make script. When I ran the make script, it output something like:
> g++ -fPIC -O -O3 -DUSING_PCH -D_REENTRANT -I"/usr/local/include/boost" -I"/usr/local/." -I"../src" -I"/opt/xerces-c-3.1.1/src" -c -o A/B.h.gch A/B.cpp
>
> Not sure whether it used -o instead of -x causing the problem.
>
> Any suggestion?
That is compiling a .cpp file, not a .h file. gcc will not generate a
PCH file if you compile a .cpp file, it will generate an object file.
If that .cpp file is really a header file with an unusual name, then
you can use the -x c++-header option to get gcc to generate a PCH.
Ian
