I'm following the instructions in the CMake FAQ entry "How can I build my MSVC application with a static runtime?" to centralize selection of the MSVC runtime for a bunch of nested CMake projects (they are pulled in as Git submodules and added to the master project using CMake's find_package() directive).
So, I wrote this CMake macro:
macro(configure_msvc_runtime) if(MSVC) # Default to statically-linked runtime. if("${MSVC_RUNTIME}" STREQUAL "") set(MSVC_RUNTIME "static") endif() # Set compiler options. set(variables CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELEASE CMAKE_C_FLAGS_RELWITHDEBINFO CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELEASE CMAKE_CXX_FLAGS_RELWITHDEBINFO ) if(${MSVC_RUNTIME} STREQUAL "static") message(STATUS "MSVC -> forcing use of statically-linked runtime." ) foreach(variable ${variables}) if(${variable} MATCHES "/MD") string(REGEX REPLACE "/MD" "/MT" ${variable} "${${variable}}") endif() endforeach() else() message(STATUS "MSVC -> forcing use of dynamically-linked runtime." ) foreach(variable ${variables}) if(${variable} MATCHES "/MT") string(REGEX REPLACE "/MT" "/MD" ${variable} "${${variable}}") endif() endforeach() endif() endif() endmacro() I call this macro at the beginning of my root CMakeLists.txt (before any add_library() or add_executable() call is made) and add a little bit of debugging prints:
configure_msvc_runtime() set(variables CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELEASE CMAKE_C_FLAGS_RELWITHDEBINFO CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELEASE CMAKE_CXX_FLAGS_RELWITHDEBINFO ) message(STATUS "Initial build flags:") foreach(variable ${variables}) message(STATUS " '${variable}': ${${variable}}") endforeach() message(STATUS "") Then, I run CMake to generate a Visual Studio solution like so:
cmake -G "Visual Studio 9 2008" ..\.. -DMSVC_RUNTIME=dynamic and I get the following outputs:
-- MSVC -> forcing use of dynamically-linked runtime. -- Initial build flags: -- 'CMAKE_C_FLAGS_DEBUG': /D_DEBUG /MDd /Zi /Ob0 /Od /RTC1 -- 'CMAKE_C_FLAGS_MINSIZEREL': /MD /O1 /Ob1 /D NDEBUG -- 'CMAKE_C_FLAGS_RELEASE': /MD /O2 /Ob2 /D NDEBUG -- 'CMAKE_C_FLAGS_RELWITHDEBINFO': /MD /Zi /O2 /Ob1 /D NDEBUG -- 'CMAKE_CXX_FLAGS_DEBUG': /D_DEBUG /MDd /Zi /Ob0 /Od /RTC1 -- 'CMAKE_CXX_FLAGS_MINSIZEREL': /MD /O1 /Ob1 /D NDEBUG -- 'CMAKE_CXX_FLAGS_RELEASE': /MD /O2 /Ob2 /D NDEBUG -- 'CMAKE_CXX_FLAGS_RELWITHDEBINFO': /MD /Zi /O2 /Ob1 /D NDEBUG Now, the thing is that when I start Visual Studio and examine the project properties under "C/C++, Code Generation", I see that the "Runtime Library" setting is not consistent with the options printed in the shell. Under the "Release", "MinSizeRel" and "RelWithDebInfo" configurations, I get the expected results ("Multi-threaded DLL /MD", but the "Debug" configuration still displays "Multi-threaded /MT".
Also, when I force use of the statically-linked runtime, I get similar results. If I run
cmake -G "Visual Studio 9 2008" ..\.. -DMSVC_RUNTIME=static I get the following outputs:
-- MSVC -> forcing use of statically-linked runtime. -- Initial build flags: -- 'CMAKE_C_FLAGS_DEBUG': /D_DEBUG /MTd /Zi /Ob0 /Od /RTC1 -- 'CMAKE_C_FLAGS_MINSIZEREL': /MT /O1 /Ob1 /D NDEBUG -- 'CMAKE_C_FLAGS_RELEASE': /MT /O2 /Ob2 /D NDEBUG -- 'CMAKE_C_FLAGS_RELWITHDEBINFO': /MT /Zi /O2 /Ob1 /D NDEBUG -- 'CMAKE_CXX_FLAGS_DEBUG': /D_DEBUG /MTd /Zi /Ob0 /Od /RTC1 -- 'CMAKE_CXX_FLAGS_MINSIZEREL': /MT /O1 /Ob1 /D NDEBUG -- 'CMAKE_CXX_FLAGS_RELEASE': /MT /O2 /Ob2 /D NDEBUG -- 'CMAKE_CXX_FLAGS_RELWITHDEBINFO': /MT /Zi /O2 /Ob1 /D NDEBUG And yet all configurations produce the "Multi-threaded /MT" value for the "Runtime Library" setting.
Can someone tell me what I'm doing wrong, or if this is a bug in CMake (2.8.7) or something ?
For what it's worth, If I generate Visual Studio 2010 project files, I get a different value for the "Debug" configuration, but still not the one I selected. In all cases, the setting appears in regular font for the "Debug" configuration whereas it appears in bolded font for the other configurations, hinting that those are overrides. Moreover, if I open the XML project files, I find that the "Debug" configuration has no setting for the "RuntimeLibrary" attribute of the "Tool" element with the "Name=VCCLCompilerTool" attribute. All other configurations have an explicit setting.