mingw-g++ can't find include directory - c++

Question

I'm trying to compile my program for Windows, on Linux, so I installed the w64-mingw32 compiler via the Debian package manager. I made a separate cmakelists file where I chose x86_64-w64-mingw32-g++ as the compiler. When I try to run my build script, I get errors where it can't find the libraries that I use in my project. This is my cmake file:
cmake_minimum_required (VERSION 3.5)
if (POLICY CMP0072)
cmake_policy(SET CMP0072 NEW)
else (NOT POLICY CMP0072)
message(STATUS "Could not use CMP0072 policy")
endif(POLICY CMP0072)
project(opengl-test LANGUAGES CXX)
set(CMAKE_CXX_COMPILER "/usr/bin/x86_64-w64-mingw32-g++")
set(CMAKE_C_COMPILER "/usr/bin/x86_64-w64-mingw32-gcc")
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
include(GNUInstallDirs)
set(CMAKE_FIND_ROOT_PATH "/usr/x86_64-w64-mingw32")
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set (source_dir "${PROJECT_SOURCE_DIR}/src/")
set (base_dir "${source_dir}/base/")
set (IMGUI_DIR "/usr/include/imgui")
set(GCC_COVERAGE_LINK_FLAGS "")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${GCC_COVERAGE_LINK_FLAGS}")
file(GLOB source_files "${source_dir}/*.cpp")
file(GLOB_RECURSE base_files "${base_dir}/*.cpp")
file(GLOB imgui_files "${IMGUI_DIR}/*.cpp")
find_package(OpenGL REQUIRED)
find_package(GLEW REQUIRED)
find_package(PkgConfig REQUIRED)
pkg_search_module(GLFW REQUIRED glfw3)
add_executable(${PROJECT_NAME} ${source_files} ${imgui_files} ${base_files})
#target_compile_features(${PROJECT_NAME} PRIVATE cxx_std_17)
message(STATUS ${OPENGL_LIBRARIES})
target_link_libraries(${PROJECT_NAME} PUBLIC ${GLFW_LIBRARIES} ${OPENGL_LIBRARIES} ${GLEW_LIBRARIES})
A lot of the code in the cmakelists file doesn't do anything because I was trying to make it work but nothing was working. I left it in so you can see what I've tried and doesn't work.
I can run this and it compiles, but I get a linker error.
CMake Warning:
No source or binary directory provided. Both will be assumed to be the
same as the current working directory, but note that this warning will
become a fatal error in future CMake releases.
-- /usr/lib/x86_64-linux-gnu/libOpenGL.so/usr/lib/x86_64-linux-gnu/libGLX.so/usr/lib/x86_64-linux-gnu/libGLU.so
-- Configuring done
CMake Warning at CMakeLists.txt:38 (add_executable):
Cannot generate a safe runtime search path for target opengl-test because
files in some directories may conflict with libraries in implicit
directories:
runtime library [libGLEW.so.2.1] in /usr/lib64 may be hidden by files in:
/usr/lib/x86_64-linux-gnu
Some of these libraries may not be found correctly.
-- Generating done
-- Build files have been written to: /home/user/Documents/CPP-Stuff/Scrap-Framework
[29/29] Linking CXX executable opengl-test
FAILED: opengl-test
: && /usr/bin/x86_64-w64-mingw32-g++ -g CMakeFiles/opengl-test.dir/src/main.cpp.o CMakeFiles/opengl-test.dir/usr/include/imgui/imgui.cpp.o CMakeFiles/opengl-test.dir/usr/include/imgui/imgui_demo.cpp.o CMakeFiles/opengl-test.dir/usr/include/imgui/imgui_draw.cpp.o CMakeFiles/opengl-test.dir/usr/include/imgui/imgui_impl_glfw.cpp.o CMakeFiles/opengl-test.dir/usr/include/imgui/imgui_impl_opengl3.cpp.o CMakeFiles/opengl-test.dir/usr/include/imgui/imgui_tables.cpp.o CMakeFiles/opengl-test.dir/usr/include/imgui/imgui_widgets.cpp.o CMakeFiles/opengl-test.dir/src/base/Application/Application.cpp.o CMakeFiles/opengl-test.dir/src/base/Application/Window.cpp.o CMakeFiles/opengl-test.dir/src/base/GL/Cubemap.cpp.o CMakeFiles/opengl-test.dir/src/base/GL/Texture.cpp.o CMakeFiles/opengl-test.dir/src/base/GL/UniformBuffer.cpp.o CMakeFiles/opengl-test.dir/src/base/GL/VertexBuffer.cpp.o CMakeFiles/opengl-test.dir/src/base/Input/Input.cpp.o CMakeFiles/opengl-test.dir/src/base/Model/Material.cpp.o CMakeFiles/opengl-test.dir/src/base/Model/Mesh.cpp.o CMakeFiles/opengl-test.dir/src/base/Model/Model.cpp.o CMakeFiles/opengl-test.dir/src/base/Model/ModelLoader.cpp.o CMakeFiles/opengl-test.dir/src/base/Renderer/FPSCamera.cpp.o CMakeFiles/opengl-test.dir/src/base/Renderer/MaterialManager.cpp.o CMakeFiles/opengl-test.dir/src/base/Renderer/Renderbuffer.cpp.o CMakeFiles/opengl-test.dir/src/base/Renderer/Renderer.cpp.o CMakeFiles/opengl-test.dir/src/base/Scene/Lights.cpp.o CMakeFiles/opengl-test.dir/src/base/Scene/Scene.cpp.o CMakeFiles/opengl-test.dir/src/base/Scene/Skybox.cpp.o CMakeFiles/opengl-test.dir/src/base/Shader/Shader.cpp.o CMakeFiles/opengl-test.dir/src/base/Shader/ShaderManager.cpp.o -o opengl-test -Wl,-rpath,/usr/lib/x86_64-linux-gnu -lglfw /usr/lib/x86_64-linux-gnu/libOpenGL.so /usr/lib/x86_64-linux-gnu/libGLX.so /usr/lib/x86_64-linux-gnu/libGLU.so /usr/lib64/libGLEW.so && :
/usr/bin/x86_64-w64-mingw32-ld: cannot find -lglfw
/usr/bin/x86_64-w64-mingw32-ld: /usr/lib/x86_64-linux-gnu/libOpenGL.so: error adding symbols: file in wrong format
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
The include files are located in /usr/include/, but I also put them in /usr/x86_64-w64-mingw32/include/.
Does anyone know how I can fix this, or a better way to compile for Windows on Linux?

Answer 1

You need to build the libraries you're using for Windows, or find prebuilt ones, e.g. in MSYS2 repositories. You also need to point CMake to those libraries.
I've made Quasi-MSYS2 to automate both.
Example usage:
# Install Clang, LLD, Wine. Then:
git clone https://github.com/holyblackcat/quasi-msys2
cd quasi-msys2/
make install _gcc _glfw _glew
env/shell.sh
# Build
cd your/project/location
mkdir build
cd build
cmake ..
make
# Run with Wine
./a.exe
Here is CMakeLists.txt I've used. I removed the cross-compilation stuff (which is handled automatically).
cmake_minimum_required (VERSION 3.5)
if (POLICY CMP0072)
cmake_policy(SET CMP0072 NEW)
else (NOT POLICY CMP0072)
message(STATUS "Could not use CMP0072 policy")
endif(POLICY CMP0072)
project(opengl-test LANGUAGES CXX)
find_package(OpenGL REQUIRED)
find_package(GLEW REQUIRED)
find_package(PkgConfig REQUIRED)
pkg_search_module(GLFW REQUIRED glfw3)
add_executable(a 1.cpp)
message(STATUS ${OPENGL_LIBRARIES})
target_link_libraries(a PUBLIC ${GLFW_LIBRARIES} ${OPENGL_LIBRARIES} GLEW::GLEW)
I also put them in /usr/x86_64-w64-mingw32/include/
You shouldn't modify system include directories manually. Leave them to your package manager.