GLEW + cmake链接失败“未定义引用符号glDrawElements”+“DSO从命令行中丢失”

Question

I'm linking GLEW, SDL2 and Assimp with Cmake. It seems to be working fine while building the .o files, however when linking them I get these errors

:-1: error: CMakeFiles/"Projectpath".cpp.o: undefined reference to symbol 'glDrawElements'
/usr/lib/x86_64-linux-gnu/mesa/libGL.so.1:-1: error: error adding symbols: DSO missing from command line
:-1: error: collect2: error: ld returned 1 exit status

Here's the part of the Cmakefile that links the libraries

find_package(OpenGL)
find_package(GLEW)
find_package(SDL2)
find_package(Assimp)
#Include(FindPkgConfig)
#PKG_SEARCH_MODULE(SDL2 REQUIRED sdl2)
set(INCLUDE_DIRS ${OpenGL_INCLUDE_DIRS} ${SDL2_INCLUDE_DIRS} ${GLEW_INCLUDE_DIRS} ${Assimp_INCLUDE_DIRS})
set(LIBS ${LIBS} ${OpenGL_LIBRARIES} ${SDL2_LIBRARIES} ${GLEW_LIBRARIES} ${Assimp_LIBRARIES} )
include_directories(${INCLUDE_DIRS})

target_link_libraries(${PROJECT_NAME} ${LIBS})

I tried changing the linking order as I read that could be a problem. I also added the OpenGL thing because of the libGL thing in the error, it doesn't seem to work. I also read about checking dependencies using pkg-config --print-requires --print-requires-private glew , but the problem is that it has like 20 different libraries it depends on. Would I need to link all of them?

It's not that I don't have the correct libraries, I created a basic OpenGL program on this computer last week and that worked fine (I used another way of linking my libraries and also used Code::Blocks instead of Qt-Creator)

I assume that the DSO thing is the problem after reading the answer to this question . But shouldn't that mean that doing the OpenGL thing in the cmakefile fix it?

Thanks!

EDIT: I can create VertexArrays, VertexBuffers etc. But as soon as I add in calls to either. glDrawElements(...) or glDrawArrays(...) I get that error. (I might get that error on some other functions as well, but those are the only ones I get that error on when I try to render a basic mesh)

Answer 1

The problem was that in OpenGL_INCLUDE_DIRS and OpenGL_LIRARIES is actually OPENGL_INCLUDE_DIRS (<-- not quite sure I need that one, I probably don't) and OPENGL_LIBRARY So the CmakeFile snippet I had in my question should actually look like this

find_package(OpenGL)
find_package(GLEW)
find_package(SDL2)
find_package(Assimp)
#Include(FindPkgConfig)
#PKG_SEARCH_MODULE(SDL2 REQUIRED sdl2)
set(INCLUDE_DIRS ${INCLUDE_DIRS} ${OPENGL_INCLUDE_DIRS} ${SDL2_INCLUDE_DIRS} ${GLEW_INCLUDE_DIRS} ${Assimp_INCLUDE_DIRS}) #<--- Changed this from ${OpenGL_INCLUDE_DIRS} to ${OPENGL_INCLUDE_DIRS} (Again not sure I need that variable)
set(LIBS ${LIBS} ${OPENGL_LIBRARY} ${SDL2_LIBRARIES} ${GLEW_LIBRARIES} ${Assimp_LIBRARIES} ) #<---(Changed this from ${OpenGL_LIBRARIES} to ${OPENGL_LIBRARY}
include_directories(${INCLUDE_DIRS})

target_link_libraries(${PROJECT_NAME} ${LIBS})

And that fixed it! :)

Answer 2

I got a similar issue configuring GLEW, with CMake, applying to the basic tutorial #2 from http://www.opengl-tutorial.org for testing purpose.

I am using GLFW instead of SDL, but the root cause is the same.

With recent CMake (>= 3.1), we simply need:

find_package(OpenGL REQUIRED)
target_link_libraries( myApp OpenGL::GL )

find_package ( GLEW REQUIRED )
target_link_libraries( myApp GLEW::GLEW )   

As you pointed out, we got an "undefined reference" issue if not looking for openGL.