Re: passing flags to C compiler but not to C++ compiler

[Robert Boehne]

On 07/27/13 00:32, Vincent Torri wrote:
> hello
>
> in my sources, i have both C and C++ files. Something like
>
> my_lib_la_SOURCES = foo.c foo.cpp
>
> I want to pass, for example, -Wdeclaration-after-statement to gcc. Hence,
> when compiling foo.cpp, i have the warning :
>
> cc1plus.exe: warning: command line option '-Wdeclaration-after-statement'
> is valid for C/ObjC but not for C++
>
> How can I remove this warning when compiling c++ files ?
>
> thank you
>
> Vincent Torri

I misread - for C and not C++ you should set "CFLAGS"

./configure CFLAGS="-g -O2 -Wdeclaration-after-statement" CXXFLAGS="-g -O2"

for example.  If you want to pass something to the preprocessor,
it's used by both C and C++, use CPPFLAGS
CPPFLAGS="-DSYMBOL=value -I/path/to/headers"

You can set them in the environment, but if you use the syntax where 
it's after
the configure in the command, those settings will be saved in config.log
so you can see what they were set to when you built.

HTH,

Robert Boehne