How to get CMake find_library to find correct library for build type

Question

I'm trying to get find_library in CMake to correctly find a third party library for linking into my project. However, it is returning the 32bit version of the library even though the build target is 64bit. Is there a way to force it to use the correct library based on the build target?

I have a directory which contains two versions of a library, someLib.lib (32 bit) and someLib_64.lib (64 bit).

I used the Visual Studio 2019 CMake template to create a new project with a debug x64 configuration. When I attempt to build the project I get an error as it is trying to link the 32 bit library to the 64 bit application. Looking in the CMake variable cache shows that the find_library call has resolved to someLib.lib instead of someLib_64.lib. This happens even if I specify someLib_64 under the NAMES clause of the find_library call.

cmake_minimum_required (VERSION 3.8)

find_path (LIB_INCLUDE_DIR someLib.h c:/Progra~1/someLib/include /usr/include)

find_library (SOME_LIB NAMES someLib_64 HINTS c:/Progra~1/someLib/Lib /usr/lib)
if (NOT DEFINED ${SOME_LIB})
    find_library (SOME_LIB NAMES someLib HINTS c:/Progra~1/someLib/Lib /usr/lib)
endif (NOT DEFINED ${SOME_LIB})

# Add source to this project's executable.
add_executable (myProject "myProject.cpp" "myProject.h")
target_link_libraries (myProject ${SOME_LIB})
target_include_directories (myProject PUBLIC ${LIB_INCLUDE_DIR})

I would expect this to return c:/Program Files/SomeLib/Lib/someLib_64.lib but instead it returns c:/Program Files/SomeLib/Lib/someLib.lib. Is there a way to get it to correctly link the 64 bit library when building a 64 bit project?

Answer 1

Turns out it was a simple solution - I had to delete and recreate the CMake cache (Project -> CMake Cache -> Delete Cache). As I was developing the script at some point it had bound to the 32 bit version and despite selecting generate cache it wasn't actually updating the variable assignment.