[CMake] CMAKE 2.8.9, OS X 10.8 and OpenGL

[Michael Jackson]

SET(CMAKE_C_COMPILER "clang")
SET(CMAKE_CXX_COMPILER "clang++")

Those really will have no effect. If you want to use Clang, then set the CC and CXX environment variables BEFORE running cmake for the first time. By the time CMake gets to those lines the C and C++ compilers are already set and can not be changed.
___________________________________________________________
Mike Jackson                    Principal Software Engineer
BlueQuartz Software                            Dayton, Ohio
mike.jackson at bluequartz.net              www.bluequartz.net

On Aug 15, 2012, at 5:52 PM, Jason T. Slack-Moehrle wrote:

> Hi Benjamin,
> 
> I modified my CMakeLists.txt file a bit:
> 
> PROJECT(Test)
> 
> SET(TEST_VERSION 0.1+devel)
> SET(PROJECT_NAME test)
> CMAKE_MINIMUM_REQUIRED(VERSION 2.8.9)
> SET(CMAKE_INCLUDE_CURRENT_DIR TRUE)
> 
> SET(CMAKE_C_COMPILER "clang")
> SET(CMAKE_CXX_COMPILER "clang++")
> 
> SET(CMAKE_CXX_FLAGS "-std=c++11 -stdlib=libc++")
> 
> IF(APPLE)
>   find_package(OpenGL REQUIRED)
>   include_directories(${OPENGL_INCLUDE_DIR})
> 
>   INCLUDE_DIRECTORIES ( /System/Library/Frameworks )
>   FIND_LIBRARY(COCOA_LIBRARY Cocoa)
>   FIND_LIBRARY(GLUT_LIBRARY GLUT )
>   FIND_LIBRARY(OpenGL_LIBRARY OpenGL )
>   MARK_AS_ADVANCED (COCOA_LIBRARY
>                     GLUT_LIBRARY
>                     OpenGL_LIBRARY)
>   SET(EXTRA_LIBS ${COCOA_LIBRARY} ${GLUT_LIBRARY} ${OpenGL_LIBRARY})
> ENDIF (APPLE)
> #target_link_libraries(Test ${EXTRA_LIBS})
> 
> add_executable(Test main.cpp)
> 
>> for OpenGL, better use the shipped find module (see "cmake --help-module
>> FindOpenGL"):
>> 
>> find_package(OpenGL REQUIRED)
>> include_directories(${OPENGL_INCLUDE_DIR})
>> [...]
>> target_link_libraries(Test ${OPENGL_LIBRARIES})
> 
> I get errors:
> 
> $ make
> Scanning dependencies of target Test
> [100%] Building CXX object CMakeFiles/Test.dir/main.cpp.o
> Linking CXX executable Test
> Undefined symbols for architecture x86_64:
>  "_glClear", referenced from:
>      display() in main.cpp.o
>  "_glViewport", referenced from:
>      reshape(int, int) in main.cpp.o
>  "_glutCreateWindow", referenced from:
>      _main in main.cpp.o
>  "_glutDisplayFunc", referenced from:
>      _main in main.cpp.o
>  "_glutIdleFunc", referenced from:
>      _main in main.cpp.o
>  "_glutInit", referenced from:
>      _main in main.cpp.o
>  "_glutInitDisplayMode", referenced from:
>      _main in main.cpp.o
>  "_glutInitWindowSize", referenced from:
>      _main in main.cpp.o
>  "_glutMainLoop", referenced from:
>      _main in main.cpp.o
>  "_glutPostRedisplay", referenced from:
>      idle() in main.cpp.o
>  "_glutReshapeFunc", referenced from:
>      _main in main.cpp.o
>  "_glutSwapBuffers", referenced from:
>      display() in main.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]: *** [Test] Error 1
> make[1]: *** [CMakeFiles/Test.dir/all] Error 2
> make: *** [all] Error 2
> 
>> Furthermore, I suggest using an out-of-source build. I cannot answer your
>> other question. On my Linux system I do not get these error messages.
> 
> Can you tell me what you mean by 'out-of-source build"?
> 
> -Jason
> --
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