how to convert qmake.pro file to cmake [duplicate] - c++

Question

I have a .pro file on my project, but now I want to port it to a CMakeLists.txt file. How can I do this?
QT += core
QT -= gui
CONFIG += c++11
TARGET = test
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
QT += network
SOURCES += main.cpp \
test_interface.cpp \
motomanlibrary.cpp \
processing.cpp
SOURCES += main.cpp \
test_interface.h \
motomanlibrary.h \
processing.h

Answer 1

QMake: The required libraries.
QT += core
QT -= gui
QT += network
CMake: only the add is necessary. An exclude (QT -= gui) is not required.
find_package(Qt5Core REQUIRED)
find_package(Qt5Network REQUIRED)
QMake: Additional Compiler flags:
CONFIG += c++11
CMake: Extend the list of compiler flags as required.
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")
QMake: The source files
SOURCES += main.cpp \
test_interface.cpp \
motomanlibrary.cpp \
processing.cpp
CMake: Create a list of source files
set(SOURCES
main.cpp
test_interface.cpp
motomanlibrary.cpp
processing.cpp
)
QMake: The header to be included:
SOURCES += main.cpp \
test_interface.h \
motomanlibrary.h \
processing.h
CMake: Just show where the header files are.
include_directory(.) # or include_directory(${CMAKE_CURRENT_SOURCE_DIR})
include_directory(some/where/else)
QMake: The target to be built:
TARGET = test
CMake: Set the name of the target, add the sources, link the required libs.
add_executable(test ${SOURCES} )
qt5_use_modules(test Core Network) # This macro depends from the Qt version
# Should not be necessary
#CONFIG += console
#CONFIG -= app_bundle
#TEMPLATE = app
See further details on Convert qmake to cmake

Answer 2

There is a python script to convert QMake to CMake on a WIP branch of Qt Base: https://code.qt.io/cgit/qt/qtbase.git/tree/util/cmake/pro2cmake.py?h=wip/cmake
It will probably be released with Qt 6 when CMake will become the main build system.

Answer 3

This is what you would typically write in a simple Qt application built with cmake consuming Qt. A few gotchas:
Use automoc. This reduces the maintenance overhead significantly. It is also fast enough even for large projects so that you do not need to care about build-time slow-down.
Use versionless cmake targets so that they are compatible across Qt versions.
If you can, take advantage of the QT_DISABLE_DEPRECATED_BEFORE variable.
As a bonus, enable some usual warning, error and sanitizer detections if you aim for high quality.
You may or may not want to add a Qt 5 fallback in case anyone would like to use your software with Qt 5. This requirement may phase out slowly, but surely.
project(Application VERSION 1.0.0 LANGUAGES CXX)
set(CMAKE_CXX_STANDARD 23)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_AUTOUIC ON)
find_package(Qt6 COMPONENTS Widgets)
if (NOT Qt6_FOUND)
find_package(Qt5 5.15 REQUIRED COMPONENTS Widgets)
endif()
if (CMAKE_CXX_COMPILER_ID MATCHES "(Clang|GNU)")
add_compile_options(-Wall -Wpedantic -Wextra -Werror)
add_compile_options(-fsanitize=address -fsanitize=undefined -fno-omit-frame-pointer)
add_link_options(-fsanitize=address -fsanitize=undefined -fno-omit-frame-pointer)
elseif (CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
set_property(DIRECTORY APPEND PROPERTY COMPILE_OPTIONS "/w")
endif()
add_compile_definitions(QT_DISABLE_DEPRECATED_BEFORE=0xFFFFFF)
add_executable(Application
mainwindow.cpp
main.cpp
)
target_link_libraries(Application Qt::Widgets)