[SOLVED] A missing header from a repository which is linked to a shared library that is linked to my project, using cmake

Issue

I have a GitHub repository containing two cmake projects. Lets say the name of the repo is "Audio" and it contains a directory "AudioGui" and a directory "AudioLib". The "AudioLib" project is a shared library which includes and links a header from another GitHub repository.

AudioLib can be built and its cmake contains:

include(FetchContent)

FetchContent_Declare(
  AudioFile
  GIT_REPOSITORY https://github.com/adamstark/AudioFile.git
  GIT_TAG        1.1.0
)

FetchContent_MakeAvailable(AudioFile)


target_link_libraries(AudioLib PUBLIC
  Qt${QT_VERSION_MAJOR}::Core
  AudioFile
)

AudioGui, which cannot be built but cmake returns no errors, contains in its cmake:

include(FetchContent)
FetchContent_Declare(
  Audio
  GIT_REPOSITORY https://github.com/myname/Audio.git
  GIT_TAG        1.0.1
)

FetchContent_MakeAvailable(Audio)

target_link_libraries(AudioGui PUBLIC
  Qt${QT_VERSION_MAJOR}::Widgets
  Audio
)

The problem is that the includes of the headers inside AudioGui can be done this way: #include "_deps/audio-src/AudioLib/Converter_global.h" #include "_deps/audio-src/AudioLib/converter.h" instead of #include "AudioLib/Converter_global.h" #include "AudioLib/converter.h" and even in that way I get an error that the header AudioFile.h (which is included in AudioLib and directly to AudioGui) cannot be found.

Any ideas on what I am doing wrong?

Solution

Since AudioFile is a third party library for the client programs, AudioFile.h must not be included in AudioLib's headers (a pointer and a forward declaration of AudioFile should be used instead in order to not having external dependencies). You can see the full CmakeLists files here: https://michae9.wordpress.com/2022/09/01/shared-lib-to-be-used-by-client-programs-with-cmake/

Answered By - michalis

Answer Checked By - Terry (WPSolving Volunteer)