7 files changed, 173 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..872afed
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+moc_*
+ui_*
+run
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..4ba3ce9
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,26 @@
+QTINCPATH = /usr/include/qt6
+QTTOOLS = /usr/lib64/qt6/libexec
+
+CC = g++
+MOC = ${QTTOOLS}/moc
+UIC = ${QTTOOLS}/uic
+INCLUDE = -I ${QTINCPATH} \
+          -I ${QTINCPATH}/QtWidgets
+QTLIB = -lQt6Widgets \
+        -lQt6Core \
+        -lQt6Gui
+SRC = main.cpp mainwindow.cpp moc_mainwindow.cpp
+
+all: moc ui
+        ${CC} ${SRC} ${INCLUDE} ${QTLIB} -o run
+
+moc:
+        ${MOC} mainwindow.h > moc_mainwindow.cpp
+
+ui:
+        ${UIC} mainwindow.ui > ui_mainwindow.h
+
+clean:
+        rm moc_* ui_* run
+
+.PHONY: all moc ui clean
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..a56ea9e
--- /dev/null
+++ b/README.md
@@ -0,0 +1,80 @@
+# A minimal QT application, without the nonsense
+
+This repository contains a minimal QT application that can be compiled
+without using CMake or QT Creator.
+
+## Requirements
+
+* A C++ compiler (tested with GCC 14.2.1 and Clang 19.1.7, both on Linux-x86_64)
+* QT libraries and headers
+* The QT development tools `moc` and `uic`
+
+On Fedora Linux they are contained in the `qt6-qtbase-devel`. I have
+not tested this on other operating systems.
+
+## tl;dr
+
+If you just want to try out this program you can run (if you have `make` installed)
+
+```
+$ make && ./run
+```
+
+## Explanation
+
+Following the most basic QT Creator template, there are 4 source code files:
+
+* `main.cpp`: the main source file
+* `mainwindow.h`: the header file for the main window of the application
+* `mainwindow.cpp`: the C++ source for the main window
+* `mainwindow.ui`: the UI file with an XML description of the main window
+
+The compilation is done in 3 steps:
+
+1. Pre-process `mainwindow.h` with `moc` to obtain `moc_mainwindow.cpp`
+2. Compile `mainwindow.ui` with `uic` to obtain `ui_mainwindow.h`
+3. Compile the C++ files, including `moc_mainwindow.cpp`
+
+The `Makefile` implements these three steps.
+
+The first two steps are straightforward: first you need to locate the
+`moc` and `uic` command - they are usually in the QT installation
+folder. For example I have them in `/usr/lib64/qt/libexec`. Then run:
+
+```
+$ /usr/lib64/qt/libexec/moc mainwindow.h > moc_mainwindow.cpp
+$ /usr/lib64/qt/libexex/uic mainwindow.ui > ui_mainwindow.h
+```
+
+These steps can be skipped if one prefers to write the `moc_` and `ui_`
+files directly, removing the dependency on the two tools.
+
+For the last step, one needs to include the header files and link with
+the QT libraries.
+
+On my system the header files are in `/usr/include/qt6`. This means I
+need to add the option `-I /usr/include/qt6` to my `gcc` command. This
+simple project also requires headers contained in a subfolder of this,
+so I will add a second `-I` option (see the full command below).
+
+As for the system libraries, in my case they are installed in a system
+folder that is scanned by default by the linker, so I don't have to
+specify the path.  We need the files `libQt6Widgets.so`, `libQt6Core.so`
+and `libQt6Gui.so`, which we can include with
+`-lQt6Widgets -lQt6Core -lQt6Gui`. If your linker does not find them,
+locate them and include their folder with `-L /path/to/the/folder`.
+
+So the command for step 3 becomes:
+
+```
+$ g++ main.cpp mainwindow.cpp moc_mainwindow.cpp \
+        -I /usr/include/qt6 -I /usr/include/qt6/QtWidgets \
+        -lQt6Widgets -lQt6Core -lQt6Gui
+        -o run
+```
+
+And finally you can enjoy your new app:
+
+```
+$ ./run
+```
diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..1cd93da
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,11 @@
+#include "mainwindow.h"
+
+#include <QApplication>
+
+int main(int argc, char *argv[])
+{
+        QApplication a(argc, argv);
+        MainWindow w;
+        w.show();
+        return a.exec();
+}
diff --git a/mainwindow.cpp b/mainwindow.cpp
new file mode 100644
index 0000000..ebaa88c
--- /dev/null
+++ b/mainwindow.cpp
@@ -0,0 +1,13 @@
+#include "mainwindow.h"
+#include "./ui_mainwindow.h"
+
+MainWindow::MainWindow(QWidget *parent)
+        : QMainWindow(parent), ui(new Ui::MainWindow)
+{
+        ui->setupUi(this);
+}
+
+MainWindow::~MainWindow()
+{
+        delete ui;
+}
diff --git a/mainwindow.h b/mainwindow.h
new file mode 100644
index 0000000..ef1225e
--- /dev/null
+++ b/mainwindow.h
@@ -0,0 +1,19 @@
+#include <QMainWindow>
+
+QT_BEGIN_NAMESPACE
+namespace Ui {
+class MainWindow;
+}
+QT_END_NAMESPACE
+
+class MainWindow : public QMainWindow
+{
+        Q_OBJECT
+
+public:
+        MainWindow(QWidget *parent = nullptr);
+        ~MainWindow();
+
+private:
+        Ui::MainWindow *ui;
+};
diff --git a/mainwindow.ui b/mainwindow.ui
new file mode 100644
index 0000000..f9481ec
--- /dev/null
+++ b/mainwindow.ui
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+<class>MainWindow</class>
+
+<widget class="QMainWindow" name="MainWindow">
+        <property name="geometry">
+                <rect>
+                        <x>0</x>
+                        <y>0</y>
+                        <width>800</width>
+                        <height>600</height>
+                </rect>
+        </property>
+        <property name="windowTitle">
+                <string>My first QT app, without the nonsense!</string>
+        </property>
+</widget>
+
+<resources/>
+<connections/>
+</ui>