Import CMake Project into an existing QT Project .pro

Question

I have a QT Project I am working on, it has a couple of sub-modules, which I list in my project's .pro file as:

if(!include(module/my_module.pri)){
    error("module my_module not found")
}

What I tried:

Well, I have found a library which I intend to use, which is a CMake project libcrashreporter-qt. I am just linking the project for completeness - there is nothing wrong with this library (to my knowledge)

Problem:

I figured I will try an include the CMakeLists.txt file as I would a .pri file:

if(!include(libcrashreporter-qt/CMakeLists.txt)){
    error("module libcrashreporter-qt not found")
}

where the libcrashreporter-qt folder is in the root of my project

Some Code:

In doing so, I get a horde of compiler errors:

$project_dir/libcrashreporter-qt/CMakeLists.txt:1: 'project' is not a recognized test function.
$project_dir/libcrashreporter-qt/CMakeLists.txt:2: 'cmake_minimum_required' is not a recognized test function.
$project_dir/libcrashreporter-qt/CMakeLists.txt:4: Extra characters after test expression.
$project_dir/libcrashreporter-qt/CMakeLists.txt:5: 'cmake_policy' is not a recognized test function.
$project_dir/libcrashreporter-qt/CMakeLists.txt:6: 'endif' is not a recognized test function.
$project_dir/libcrashreporter-qt/CMakeLists.txt:10: 'find_package' is not a recognized test function.
$project_dir/libcrashreporter-qt/CMakeLists.txt:12: Opening parenthesis without prior test name.
$project_dir/libcrashreporter-qt/CMakeLists.txt:16: 'string' is not a recognized test function.
$project_dir/libcrashreporter-qt/CMakeLists.txt:17: 'string' is not a recognized test function.
$project_dir/libcrashreporter-qt/CMakeLists.txt:18: 'endif' is not a recognized test function.
$project_dir/libcrashreporter-qt/CMakeLists.txt:20: 'add_subdirectory' is not a recognized test function.
$project_dir/libcrashreporter-qt/CMakeLists.txt:21: 'add_subdirectory' is not a recognized test function.

CMake file content (note, I changed the file slightly trying to resolve build issues by removing the multi-line if-statement and commented the option line):

project(libcrashreporter-qt)
cmake_minimum_required(VERSION 3.1)

if(POLICY CMP0071)
    cmake_policy(SET CMP0071 NEW)
endif()

#option(ENABLE_GPL_CODE OFF)

find_package(Qt5 COMPONENTS Core Network Widgets)

if((CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_FLAGS) OR (UNIX AND NOT APPLE AND CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
    # Breakpad uses GNU compiler extensions like typeof.
    # Luckily these features are not used on OSX, so we can build the
    # crashreporter there with the normal C++11 standard.
    string(REPLACE "-std=c++11" "-std=gnu++11" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
    string(REPLACE "-std=c++14" "-std=gnu++14" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
endif()

add_subdirectory(3rdparty)
add_subdirectory(src)

This leads me to believe there is an issue with Qt .pro file compatibility and CMake projects being used within each other.

Question:

How can access the library functions of this CMake project, and compile it with my project (i.e. w/o changing the CMake project itself), or alternatively how best can I convert the CMake project to a compatible .pro project?

qmake and cmake are 2 different technologies so you can't join them. The only option is to create a .pro / .pri for the external library. — eyllanesc, Jan 13 '20 at 09:12

score 2 · Answer 1 · answered Jan 13 '20 at 10:18

AFAIK CMake and QMake cannot be mixed together in one project, they are two different build systems and if you want to use a CMake project in a QMake project you have "two" options:

if you want to use the source files (.cpp and .h) or even modify them in your project you have to import them to your QMake project (you can easily do that in your QtCreator) and compile all of the files of your project
if the CMake library that you are using doesn't need any change (most of the times it's like this when you're using a third party library) and you just want to import it to your project and link it against your executable, you just run and compile the CMake project (separate from your own QMake project) and then use the output dynamic or static library of that project to link against your QMake project

thanks for the answer, was hoping there would be 'import cmake as .pro' option... — CybeX, Jan 13 '20 at 10:27

score 0 · Answer 2 · answered Jan 13 '20 at 11:22

As far as I remember, in Qt you can specify the custom compiler settings for the extra target, so, if you need your CMake project to be rebuilt just before the target Qt application is built, you can try to use this way

A possible solution is here:

https://stackoverflow.com/a/15766946/2333496

Import CMake Project into an existing QT Project .pro

2 Answers2