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

[Robert Boehne]

On 07/27/13 16:26, Vincent Torri wrote:
> On Sat, Jul 27, 2013 at 10:24 PM, Robert Boehne <address@hidden> wrote:
> > 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"
> it will still not work as $(CFLAGS) will be passed to the compilation
> of the c++ source file
>
> Vincent Torri

Are you saying you've tried it?  That's not my understanding of how Automake
(or GNU Make) works.  Unless the project has overridden the default
use for these variables, that's how it's supposed to work, and
this problem is an example of why.

This is the relevant section of the manual:

http://www.gnu.org/software/automake/manual/automake.html#Standard-Configuration-Variables

> > 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