CODEWITHSUNDEEP
cgcccmakemingwclion
PentaKon
PentaKon

Reputation: 4636

CMake fails to find library

I have a project in CLion that uses CMake. I have added a list of directories using the include_directories command and although the IDE finds them properly and provides auto-complete and the includes seem to link properly, when I try to run the program I get errors of undefined references to all functions.

Updated CMake file:

cmake_minimum_required(VERSION 3.9)
project(Test C)

set(CMAKE_C_STANDARD 11)
set(C_LIBRARIES_DIR E:/Work\ Related\ General/C\ Projects/Libraries)

# set paths (only needed on windows)
if(${CMAKE_SYSTEM_NAME} STREQUAL "Windows")
  # where is the SDL2 development package copied to?
  set(SDL2_PATH "${C_LIBRARIES_DIR}/SDL2-2.0.8/i686-w64-mingw32")

  # add path do search path (windows requires ";" instead of ":" )
  set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${C_LIBRARIES_DIR}/SDL2")
endif()

find_package(SDL2 REQUIRED)

include_directories(${SDL2_INCLUDE_DIR})

add_executable(Test src/main.c)

target_link_libraries(Test ${SDL2_LIBRARY})

And the error I'm getting is the following:

"C:\Program Files\JetBrains\CLion 2017.3\bin\cmake\bin\cmake.exe" --build "E:\Work Related General\C Projects\Test\cmake-build-debug" --target Test -- -j 2
[ 25%] Linking C executable Test.exe
c:/mingw/bin/../lib/gcc/mingw32/6.3.0/../../../libmingw32.a(main.o):(.text.startup+0xa0): undefined reference to `WinMain@16'
collect2.exe: error: ld returned 1 exit status
mingw32-make.exe[3]: *** [Test.exe] Error 1
CMakeFiles\Test.dir\build.make:152: recipe for target 'Test.exe' failed
mingw32-make.exe[2]: *** [CMakeFiles/Test.dir/all] Error 2
CMakeFiles\Makefile2:66: recipe for target 'CMakeFiles/Test.dir/all' failed
mingw32-make.exe[1]: *** [CMakeFiles/Test.dir/rule] Error 2
CMakeFiles\Makefile2:78: recipe for target 'CMakeFiles/Test.dir/rule' failed
mingw32-make.exe: *** [Test] Error 2
Makefile:117: recipe for target 'Test' failed

I can never find good help regarding CMake online and the fact that the IDE properly recognizes the libraries but fails to link baffles me since CLion and CMake should be taking care of that... What am I missing?

UPDATE Adding the following directive before the SDL include allowed gcc to properly link: #define SDL_MAIN_HANDLED

From what I read, SDL.h itself redefines the main function to SDL_main inside its header file. Adding this directive undefines it (sort of). The goal however is to make the program run without this (since this directive is for command line programs). Still no clue there...

Upvotes: 1

Views: 1336

Answers (2)

Ansver
Ansver

Reputation: 94

As I know when you want use SDL2 then you need link next libraries -lmingw32 -lSDL2main(libSDL2main) that hold WinMain function -lSDL2(libSDL2.dll.a) and apply the flag -mwindows. For the first I suggest you link this libraries and flags by you hands with full path to libraries. Also if you want to know what you variable store you can write message. You problem it's exactly linking.

Upvotes: 1

Thaw
Thaw

Reputation: 861

You may need to add a link_directories() directive

Also, you may be able to use pkg_check_modules() to reference SDL instead. The following may not be exactly what you need, but should give you the idea

include(FindPkgConfig)
pkg_check_modules(ALL REQUIRED sdl2)

include_directories(${ALL_INCLUDE_DIRS})
link_directories(${ALL_LIBRARY_DIRS})

add_executable(Test main.c)

target_link_libraries(Test ${ALL_LIBRARIES})

Upvotes: 0

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