CMake, Microsoft Visual Studio, and Monolithic Runtimes

Question

I'm building a file using the CMake Build System and Microsoft's Visual C++ compiler. When I have CMake generate the visual studio project, the project contains the commandline to build a "Multi Threaded DLL" type of runtime -- one which depends on msvcrt.dll. For various reasons I'm not going into right now, I cannot depend on msvcrt.

Is there a way to tell CMake to modify this option in it's construction process?

Answer 1

I use the following piece of code to link to the static CRT:

if(MSVC)
# We statically link to reduce dependencies
foreach(flag_var CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
    if(${flag_var} MATCHES "/MD")
        string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
    endif(${flag_var} MATCHES "/MD")
    if(${flag_var} MATCHES "/MDd")
        string(REGEX REPLACE "/MDd" "/MTd" ${flag_var} "${${flag_var}}")
    endif(${flag_var} MATCHES "/MDd")
endforeach(flag_var)
endif(MSVC)

Answer 2

I replace the dynamic flags (/MD and /MDd) with static flags (/MT and /MTd). Also, I found that I needed to cache the flag variables in order for it to stick.

if(MSVC)
    foreach(flag_var CMAKE_C_FLAGS_DEBUG CMAKE_CXX_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE CMAKE_CXX_FLAGS_RELEASE CMAKE_C_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELWITHDEBINFO CMAKE_CXX_FLAGS_RELWITHDEBINFO) 
        string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
        string(REGEX REPLACE "/MDd" "/MTd" ${flag_var} "${${flag_var}}")
    endforeach(flag_var)
    SET (CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG}" CACHE STRING "MSVC C Debug MT flags " FORCE)    
    SET (CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}" CACHE STRING "MSVC CXX Debug MT flags " FORCE)
    SET (CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}" CACHE STRING "MSVC C Release MT flags " FORCE)
    SET (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE}" CACHE STRING "MSVC CXX Release MT flags " FORCE)
    SET (CMAKE_C_FLAGS_MINSIZEREL "${CMAKE_C_FLAGS_MINSIZEREL}" CACHE STRING "MSVC C Debug MT flags " FORCE)    
    SET (CMAKE_CXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL}" CACHE STRING "MSVC C Release MT flags " FORCE)
    SET (CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_RELWITHDEBINFO}" CACHE STRING "MSVC CXX Debug MT flags " FORCE)    
    SET (CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO}" CACHE STRING "MSVC CXX Release MT flags " FORCE)
endif()