Issues adding GLFW source to a CMake project

support
1

I’m a new one here, so hi everyone! : )

I’m having a lot of issues with building GLFW from source in my CMake project.
I’ve added the source from the “latest” branch as a git submodule in a vendor folder.
I’ve read the docs on the GLFW site, but I get a linking error when building with my project; here is the CMakeError.log:

ld.lld: error: undefined symbol: pthread_create
>>> referenced by ld-temp.o
>>>               lto.tmp:(main)

ld.lld: error: undefined symbol: pthread_detach
>>> referenced by ld-temp.o
>>>               lto.tmp:(main)

ld.lld: error: undefined symbol: pthread_join
>>> referenced by ld-temp.o
>>>               lto.tmp:(main)
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I also tried to compile and link with GCC and ld, but the problem remains.

The strange thing is that when building just GLFW (using CMake) I don’t get any errors.

If it can help, here is the GLFW-related part of my CMakeLists.txt:

set(GLFW_BUILD_DOCS OFF CACHE BOOL "" FORCE)
set(GLFW_BUILD_TESTS OFF CACHE BOOL "" FORCE)
set(GLFW_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)
add_subdirectory(vendor/glfw)
target_link_libraries(${PROJECT_NAME} glfw)

How could I fix the issue?

Thanks

2

We’ve made an example cmake starter project for GLFW on Github:

Feel free to take a look at the CMakeLists.txt file and use that for help. It looks like you’re missing the ${GLFW_LIBRARIES} variable from your target_link_libraies, this is a list of all the libraries required by GLFW for your system, you will likely also need ${OPENGL_LIBRARIES} which is created by find_package( OpenGL REQUIRED ).

3

Hi Doug, thanks for the fast reply.
I’ve modified my CMakeLists.txt as you suggested, but I still get the same error.
Here’s my full CMakeLists.txt:

cmake_minimum_required(VERSION 3.5)

project(CppSnake)

set(HEADER_FILES Apple.hpp IndexBuffer.hpp Quad.hpp Random.hpp Renderer.hpp Shader.hpp Snake.hpp Vertex.hpp VertexArray.hpp VertexBuffer.hpp VertexBufferLayout.hpp)

add_executable(${PROJECT_NAME} main.cpp ${HEADER_FILES})

target_include_directories(${PROJECT_NAME} vendor/glad/include vendor/glfw/include)

add_subdirectory(vendor/glad)
target_link_libraries(${PROJECT_NAME} glad)
target_link_libraries(${PROJECT_NAME} dl)

set(GLFW_BUILD_DOCS OFF CACHE BOOL "" FORCE)
set(GLFW_BUILD_TESTS OFF CACHE BOOL "" FORCE)
set(GLFW_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)
find_package(OpenGL REQUIRED)
add_subdirectory(vendor/glfw)
target_link_libraries(${PROJECT_NAME} glfw ${OPENGL_LIBRARIES} ${GLFW_LIBRARIES})

target_link_libraries(${PROJECT_NAME} GL)

I really don’t understand why it is complaining about pthread things

4

Could you first try using the project from https://github.com/juliettef/GLFW-CMake-starter and then if that works for you it should be possible for you to build up your own project by referencing that one.

5

Turns out the problem was the order I wrote things.
I had to first add GLFW’s subdirectory, and then do everything else, except for including GLFW’s include directory, a thing that its CMake file does automatically.
The sad part is that on glfw.org/docs/latest/build.html I couldn’t find any info about this : /
Maybe it’s just because I’m inexperienced, but I think that the GLFW team should add more info about this in the docs, it could save a lot of time for people like me :sweat_smile:

Here is my updated CMakeLists.txt, in case somebody will come across the same issue

cmake_minimum_required(VERSION 3.5)

project(CppSnake)

set(GLFW_BUILD_EXAMPLES OFF CACHE BOOL "GLFW lib only")
set(GLFW_BUILD_TESTS OFF CACHE BOOL "GLFW lib only")
set(GLFW_BUILD_DOCS OFF CACHE BOOL "GLFW lib only")
set(GLFW_BUILD_INSTALL OFF CACHE BOOL "GLFW lib only")
add_subdirectory(vendor/glfw)
add_subdirectory(vendor/glad)

set(HEADER_FILES Apple.hpp IndexBuffer.hpp Quad.hpp Random.hpp Renderer.hpp Shader.hpp Snake.hpp Vertex.hpp VertexArray.hpp VertexBuffer.hpp VertexBufferLayout.hpp)
add_executable(${PROJECT_NAME} main.cpp ${HEADER_FILES})

target_link_libraries(${PROJECT_NAME} glad glfw ${OPENGL_LIBRARIES} ${GLFW_LIBRARIES})

Thanks again to @dougbinks and all the GLFW team!

6

Note that I see you use target_link_libraries multiple times for the same project in the original version. I do not know if this is supported by cmake and so using one target_link_libraries for all libraries you want to link is best - if you need to you can concatenate them into a variable then use that.

Your current cmake adds dl and GL directly, so won’t work cross platform. Hence our starter uses ${OPENGL_LIBRARIES} and ${GLFW_LIBRARIES}.

7

Oh, I see, you’re right. I’ll edit my CMake file and my previous post. Thanks again!