Building a shared lib that depends on velocypack gives linking error (MSVC)

[gdmiron]

I am trying to compile a library that links to velocypack for windows using MSVC (Visual Studio) complier but I get linking errors due to the static vs dynamic symbols mismatch.

  Auto build dll exports
velocypack.lib(Version.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MT_StaticRelease' doesn't match value 'MD_DynamicRelease' in DatabaseClient.obj

Could you suggest a solution? Is there a way to build a shared lib for velocypack?

it works if one changes the linker settings in \cmake\Modules\AR_CompilerSettings.cmake from MTd to MDd and MT to MD. But I am not sure if this is the right solution.

[kvahed]

It is the correct solution. It just says, that you may not link statically against a dynamic library. The solution is to link dynamically against the library or build the library into a static library and then statically link againt it.

[gdmiron]

Is there a way when calling cmake to overwrite this:

      set(${flag_var} "${${flag_var}} /MT")

if I do this when building velocypack:

cmake -G"Visual Studio 15 2017" -DCMAKE_CXX_FLAGS_RELEASE=/MD -DCMAKE_BUILD_TYPE=Release

the linking is still set to /MT (probably overwritten by the code above). It only works if I manually change the flag in the file.

could you add to AR_CompilerSettings.cmake something like:

elseif(MSVC) 
    message(STATUS "Compiler type MSVC: ${CMAKE_CXX_COMPILER}")
    add_definitions("-D_CRT_SECURE_NO_WARNINGS=1")

    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 "DEBUG")
      if (MSVC_WITH_DYNAMIC_RUNTIME)
          set(${flag_var} "${${flag_var}} /MDd")
      else()
          set(${flag_var} "${${flag_var}} /MTd")
      endif()
    else ()
      if (MSVC_WITH_DYNAMIC_RUNTIME)
          set(${flag_var} "${${flag_var}} /MD")
      else()
          set(${flag_var} "${${flag_var}} /MT")
      endif()
    endif ()
  endforeach()