[CMake] Using C++ compilers for C source files?

[Robert Blake]

Aha!  Hadn't read this.  After following everyone's advice, and using  
the following section in my CMakeLists.txt file:

PROJECT(Blah)
file(GLOB_RECURSE C_FILES ${CMAKE_CURRENT_SOURCE_DIR} *.c)
set_source_files_properties(${C_FILES} PROPERTIES LANGUAGE CXX)

... I get the following make output after generating my makefiles:
make VERBOSE=1

[  1%] Building C object PrM/src/CMakeFiles/param.dir/build_mex.c.o
cd /Users/rblake/sand/carp/m/seq/PrM/src && /usr/bin/gcc    -o  
CMakeFiles/param.dir/build_mex.c.o   -c /Users/rblake/sand/carp/m/PrM/ 
src/build_mex.c
/opt/local/bin/cmake -E cmake_progress_report /Users/rblake/sand/carp/ 
m/seq/CMakeFiles 7

In other words, setting the language to CXX for this source code file  
doesn't seem to have any effect.  Any other ideas?  I'm using cmake  
2.6-patch 2, could that be the source of the problem?

Rob

On Apr 3, 2009, at 10:54 AM, Alexandre Feblot wrote:

> Hi,
>
> Look at that thread...
> http://www.cmake.org/pipermail/cmake/2009-March/028352.html
>
>
> Regards,
> Alexandre
>
> -----Original Message-----
> From: cmake-bounces at cmake.org [mailto:cmake-bounces at cmake.org] On  
> Behalf
> Of Robert Blake
> Sent: Friday, 03 April 2009 16:46
> To: cmake at cmake.org
> Subject: [CMake] Using C++ compilers for C source files?
>
> I'm converting a large mixed C++/C cmake application to C++.  The
> project has many ".c" files that I would like to compile with the C++
> compiler instead of the C compiler.  Does anyone know the proper way
> to do this in CMake?
>
> Things I've tried:
> 1.) Changing CMAKE_C_COMPILER myself: Usually CMake doesn't let you
> change CMAKE_C_COMPILER, but there are ways around that.  This way
> feels like a hack.  The output while compiling still says "Compiling
> C".  In addition, forcing CMAKE_*_COMPILER to change makes it very
> difficult to run plane cmake on Unix machines where curses is not
> installed.
>
> 2.) Tell CMake that ".c" files are in the CXX language:  I've tried
> PROJECT(Blah CXX)
> list(APPEND CMAKE_CXX_SOURCE_FILE_EXTENSIONS c)
>
> When I run CMake on my project with these changes, I get errors like:
>
> CMake Error: Cannot determine link language for target "foobar"
>
> ...for all my targets that depend only on .c files.
>
> Help!
> Rob
>
>
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