We are using cmake 2.8.11 for out project.
Our local compiler is gcc-4.4.3. There is desire to use a newer compiler, but
we are not yet ready to commit to anything yet. In the mean time we have
installed binaries gcc-4.7 and gcc-4.8. We can specify the alternate compiler
with -DCMAKE_C_COMPILER=gcc-4.7, but we want to go a step farther: one
(believed important) advantage of gcc-4.7 is the option -mtune=atom since that
is are target system. We want to force this option when using the newer
compiler, but the older version of gcc doesn't accept it.
Toolchain files are not an option, when you use a toolchain file cmake sets
CMAKE_CROSSCOMPILING meaning parts of our system that depend on running on x86
will not run. (it is up to a different team to make a build for other
processors - they are nowhere close to done but that variable is used in a few
places to disable things that my team needs).
Here is what we come up with, which both feels icky, and seems like a bad
compromise:
IF("4.8.0" STREQUAL ${CMAKE_CXX_COMPILER_VERSION} OR "4.8.1" STREQUAL
${CMAKE_CXX_COMPILER_VERSION} OR "4.8" STREQUAL ${USE_GCC_VERSION})
SET(CMAKE_CXX_COMPILER "g++-4.8")
SET(CMAKE_C_COMPILER "gcc-4.8")
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -std=c++11")
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-unused-local-typedefs" CACHE
STRING "" FORCE)
ELSEIF("4.7.1" STREQUAL ${CMAKE_CXX_COMPILER_VERSION} OR "4.7.2" STREQUAL
${CMAKE_CXX_COMPILER_VERSION} OR "4.7" STREQUAL ${USE_GCC_VERSION})
SET(CMAKE_CXX_COMPILER "g++-4.7")
SET(CMAKE_C_COMPILER "gcc-4.7")
ENDIF("4.8.0" STREQUAL ${CMAKE_CXX_COMPILER_VERSION} OR "4.8.1" STREQUAL
${CMAKE_CXX_COMPILER_VERSION} OR "4.8" STREQUAL ${USE_GCC_VERSION})
The advantage of this is you can't accidentally use gcc-4.4 and g++-4.8 - we
force them in sync. You can also set USE_GCC_VERSION on the command line and it
takes both gcc and g++, instead of having to set both CMAKE_C_COMPILER and
CMAKE_CXX_COMPILER (and the line to remember is shorter). If you do this will
work (until we upgrade gcc, but I can solve that)
What is the "right" thing to do - and why is it right?
--
Powered by www.kitware.com
Please keep messages on-topic and check the CMake FAQ at:
http://www.cmake.org/Wiki/CMake_FAQ
Kitware offers various services to support the CMake community. For more
information on each offering, please visit:
CMake Support: http://cmake.org/cmake/help/support.html
CMake Consulting: http://cmake.org/cmake/help/consulting.html
CMake Training Courses: http://cmake.org/cmake/help/training.html
Visit other Kitware open-source projects at
http://www.kitware.com/opensource/opensource.html
Follow this link to subscribe/unsubscribe:
http://www.cmake.org/mailman/listinfo/cmake
