Question

I apologize for bothering you all, but I have a little compilation problem with cmake.

I have a CMakeLists.txt file I’m using to build a test executable, and a shared library. They both have dependency to another library (SFML).

I’m using cmake on window with MinGW.

I know the name of the lib I’m building is kinda confusing with the sfml one, but it’s supposed to be a SFML wrapper, so, I didn’t find a better name!

Here the CMakeLists.txt

cmake_minimum_required(VERSION 2.6)
project(projectName)

set(EXECUTABLE_NAME testSFML)
set(LIBRARY_NAME    SFMLwindow)

set(EXECUTABLE_OUTPUT_PATH ${CMAKE_CURRENT_SOURCE_DIR}/bin/)

include_directories(${CMAKE_CURRENT_SOURCE_DIR}/include /
${CMAKE_CURRENT_SOURCE_DIR}/../../include
)

link_directories(${CMAKE_CURRENT_SOURCE_DIR}/../../lib/)

file(
    GLOB_RECURSE
    SRC_FILES
    src/*
)

file(
    GLOB_RECURSE
    INCLUDE_FILES
    include/*
)

add_executable(
${EXECUTABLE_NAME}
main.cpp
${SRC_FILES}
${INCLUDE_FILES}
)

target_link_libraries(
    ${EXECUTABLE_NAME}
    sfml-main
    sfml-system
    sfml-window
)


add_library(
${LIBRARY_NAME}
SHARED
${SRC_FILES}
)

And what I get in the terminal :

"C:\MinGW\bin\mingw32-make.exe" 
-- Configuring done
-- Generating done
-- Build files have been written to: C:/Users/iksemel/docs/WorkBench/programming/projets/TestSFML/cmake
Linking CXX shared library libSFMLwindow.dll
Creating library file: libSFMLwindow.dll.a
CMakeFiles\SFMLwindow.dir/objects.a(SFMLWindow.cpp.obj):SFMLWindow.cpp:(.text+0x59):undefined reference to `_imp___ZN2sf9VideoModeC1Ejjj'
CMakeFiles\SFMLwindow.dir/objects.a(SFMLWindow.cpp.obj):SFMLWindow.cpp:(.text+0xda): undefined reference to `_imp___ZN2sf6WindowC1ENS_9VideoModeERKSsjRKNS_15ContextSettingsE'
CMakeFiles\SFMLwindow.dir/objects.a(SFMLWindow.cpp.obj):SFMLWindow.cpp:(.text+0x163): undefined reference to `_imp___ZN2sf6Window5closeEv'
CMakeFiles\SFMLwindow.dir/objects.a(SFMLWindow.cpp.obj):SFMLWindow.cpp:(.text+0x1bd): undefined reference to `_imp___ZN2sf6Window9pollEventERNS_5EventE'
CMakeFiles\SFMLwindow.dir/objects.a(SFMLWindow.cpp.obj):SFMLWindow.cpp:(.text+0x1d8): undefined reference to `_imp___ZN2sf6Window7displayEv'
collect2: ld a retourné 1 code d'état d'exécution
mingw32-make.exe[2]: *** [libSFMLwindow.dll] Error 1
mingw32-make.exe[1]: *** [CMakeFiles/SFMLwindow.dir/all] Error 2
mingw32-make.exe: *** [all] Error 2

If anybody have a clue on what’s happening, I’d be very gratefull!

Answer 1

At a guess, your SFMLwindow library needs linked to some or all of sfml-main, sfml-system, sfml-window.

You could try changing the end of your CMakeLists.txt to:

add_library(
    ${LIBRARY_NAME}
    SHARED
    ${SRC_FILES}
    ${INCLUDE_FILES}
)

add_executable(
    ${EXECUTABLE_NAME}
    main.cpp
)

target_link_libraries(
    ${LIBRARY_NAME}
    sfml-main
    sfml-system
    sfml-window
)

target_link_libraries(
    ${EXECUTABLE_NAME}
    ${LIBRARY_NAME}
)

As an aside, file(GLOB_RECURSE... is generally frowned upon as a way to gather a list of sources. From the docs for file:

We do not recommend using GLOB to collect a list of source files from your source tree. If no CMakeLists.txt file changes when a source is added or removed then the generated build system cannot know when to ask CMake to regenerate.

Also, find_library should be preferred to link_directories in this case. From the docs for link_directories:

Note that this command is rarely necessary. Library locations returned by find_package() and find_library() are absolute paths. Pass these absolute library file paths directly to the target_link_libraries() command. CMake will ensure the linker finds them.