I have copied a sample project from GTK
#include
int main(int argc, char *argv[])
{
auto app = Gtk::Application::create(argc, argv, \"or
Solved thanks to https://github.com/DreaminginCodeZH/gtkmmproject! Final CMakeLists.txt:
cmake_minimum_required(VERSION 3.8)
project(songbook)
set(CMAKE_CXX_STANDARD 17)
find_package(PkgConfig)
pkg_check_modules(GTKMM gtkmm-3.0)
include_directories(${GTKMM_INCLUDE_DIRS})
link_directories(${GTKMM_LIBRARY_DIRS})
set(SOURCE_FILES main.cpp MainWindow.cpp MainWindow.h)
add_executable(songbook ${SOURCE_FILES})
target_link_libraries(${CMAKE_PROJECT_NAME} ${GTKMM_LIBRARIES})