CMake & QT5 - QT5_WRAP_UI not generating ui header files

Question

I have a simple CMakeLists.txt that looks like this:

CMAKE_MINIMUM_REQUIRED(VERSION 2.8)

PROJECT(calculator)

FIND_PACKAGE(Qt5Core)
FIND_PACKAGE(Qt5Gui)
FIND_PACKAGE(Qt5Widgets)

SET(CMAKE_AUTOMOC ON)
SET(CMAKE_INCLUDE_CURRENT_DIR ON)

SET(calculator_SOURCES main.cpp mainwindow.cpp)
SET(calculator_HEADERS mainwindow.h)
SET(calculator_FORMS mainwindow.ui)

QT5_WRAP_CPP(calculator_HEADERS_MOC ${calculator_HEADERS})
QT5_WRAP_UI(calculator_FORMS_HEADERS ${calculator_FORMS})

ADD_LIBRARY(calculator_CONFIG ${calculator_HEADERS_MOC} ${calculator_FORMS_HEADERS})
QT5_USE_MODULES(calculator_CONFIG Widgets)

ADD_EXECUTABLE(calculator ${calculator_SOURCES} ${calculator_CONFIG})
QT5_USE_MODULES(calculator Core Gui Widgets)

And when I try to build the project using cmake -G "Unix Makefiles" and subsequently make, the console says that ui_mainwindow.h is not found. What is the problem? Is it my cmake file?

---

Full Error Output:

[ 22%] Building CXX object CMakeFiles/calculator.dir/mainwindow.cpp.o
/home/centurion/Code/cpp/calculator/mainwindow.cpp:2:27: fatal error: ui_mainwindow.h: No such file or directory
 #include "ui_mainwindow.h"
                           ^
compilation terminated.
make[2]: *** [CMakeFiles/calculator.dir/mainwindow.cpp.o] Error 1
make[1]: *** [CMakeFiles/calculator.dir/all] Error 2
make: *** [all] Error 2

Answer 1

I was running in the same issue with cmake 3.2.2. Try using

SET(CMAKE_AUTOUIC ON)  

if the ui files are not generated. Maybe the default behaviour changed recently?

Answer 2

1. Use lower-case CMake commands. That has been the sane convention for years.

2. Why are you using both AUTOMOC and qt5_wrap_cpp? AUTOMOC is designed to replace the macro. http://www.cmake.org/cmake/help/v3.0/manual/cmake-qt.7.html#automoc

3. If using CMake 2.8.11 or later, then don't use qt5_use_modules. I wrote that as a stop-gap hack until CMake 2.8.11 was released. The target_link_libraries command does what qt5_use_modules does, but better and more-generically. http://doc-snapshot.qt-project.org/qt5-5.3/cmake-manual.html

4. The library has no sources of its own and is not used. You're clearly 'doing it wrong' here. Move the ${calculator_FORMS_HEADERS} variable usage to the executables sources. Then after addressing point 2, remove the library.