Undefined Symbols when linking project with GLFW3 using CMake on OSX - macos

Question

I am following this guide on how to build a project using GLFW3 with CMake on OSX 10.9.1, and I've run into some trouble. When I get to building the actual project I get the following errors:
$ make
Scanning dependencies of target Graphics
[100%] Building CXX object CMakeFiles/Graphics.dir/graphics.cpp.o
Linking CXX executable Graphics
Undefined symbols for architecture x86_64:
"_glBegin", referenced from:
_main in graphics.cpp.o
"_glClear", referenced from:
_main in graphics.cpp.o
"_glColor3f", referenced from:
_main in graphics.cpp.o
"_glEnd", referenced from:
_main in graphics.cpp.o
"_glLoadIdentity", referenced from:
_main in graphics.cpp.o
"_glMatrixMode", referenced from:
_main in graphics.cpp.o
"_glOrtho", referenced from:
_main in graphics.cpp.o
"_glRotatef", referenced from:
_main in graphics.cpp.o
"_glVertex3f", referenced from:
_main in graphics.cpp.o
"_glViewport", referenced from:
_main in graphics.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [Graphics] Error 1
make[1]: *** [CMakeFiles/Graphics.dir/all] Error 2
make: *** [all] Error 2
My CMakeLists.txt looks like:
cmake_minimum_required (VERSION 2.8)
project (Graphics)
# The version number.
set (Graphics_VERSION_MAJOR 1)
set (Graphics_VERSION_MINOR 0)
# configure a header file to pass some of the CMake settings
# to the source code
configure_file (
"${PROJECT_SOURCE_DIR}/GraphicsConfig.h.in"
"${PROJECT_BINARY_DIR}/GraphicsConfig.h"
)
# add the binary tree to the search path for include files
# so that we will find GraphicsConfig.h
include_directories("${PROJECT_BINARY_DIR}")
find_package(PkgConfig REQUIRED)
pkg_search_module(GLFW REQUIRED glfw3)
include_directories(${GLFW_INCLUDE_DIRS})
# add the executable
add_executable (Graphics graphics.cpp)
target_link_libraries(Graphics ${GLFW_STATIC_LIBRARIES})
# add the install targets
install (TARGETS Graphics DESTINATION bin)
install (FILES "${PROJECT_BINARY_DIR}/GraphicsConfig.h"
DESTINATION include)
However can build the project just fine using
cc `pkg-config --cflags glfw3` -o graphics graphics.cpp \
`pkg-config --static --libs glfw3`

Answer 1

I can't offer you an explanation for why one links with the OpenGL libs and the other doesn't, but the following solution worked for me with a similar problem on OSX (Mountain Lion).
At the end of the 'add executable' block, add an Apple-specific condition to link with the OpenGL framework:
# add the executable
add_executable (Graphics graphics.cpp)
target_link_libraries(Graphics ${GLFW_STATIC_LIBRARIES})
if (APPLE)
target_link_libraries(Graphics "-framework OpenGL")
endif()
I figured there must be something in the GLFW CMake config that was responsible for linking with the OpenGL libs so I had a look at the GLFW 3.0.4 CMakeLists.txt and found that '-framework' line.
This will only help you on OSX - you'd need to supply other platform specific ways of linking to make it cross platform.
You may have already considered it, but the same guide also provides a way to include the GLFW source with your app and build it that way. That's probably the easiest way to guarantee cross-platform compatibility.

Answer 2

I had to do this.
elseif(APPLE)
# GLFW
find_package(glfw3 REQUIRED)
include_directories(${GLFW_INCLUDE_DIRS})
find_package(GLEW REQUIRED)
include_directories(${GLEW_INCLUDE_DIRS})
# app_framework executable
add_executable(app_framework ${SOURCE_FILES})
target_link_libraries(app_framework app_framework_library ${GLEW_LIBRARY} glfw3)
target_link_libraries(app_framework "-framework OpenGL")
Note that I use "glfw3" instead of ${GLFW_STATIC_LIBRARIES} in target_link_library. Did not work for me otherwise.
I'm using cmake 3.6.1.

Answer 3

Add this to your CMakeFile,
add_executable(${LOCAL_PROJECT_NAME} )
#openGL Specific
target_link_libraries(${LOCAL_PROJECT_NAME} ${GLFW_STATIC_LIBRARIES})
find_package(glfw3 3.3 REQUIRED)
target_link_libraries(${LOCAL_PROJECT_NAME} glfw)
find_package(OpenGL REQUIRED)
target_link_libraries(${LOCAL_PROJECT_NAME} OpenGL::GL)
also, make sure compiler options are set accordingly.