Qt 4.8.7 Official

TEMPLATE = app QT += core gui greaterThan(QT_MAJOR_VERSION, 4): QT += widgets SOURCES += main.cpp Note: QT += widgets is ignored in Qt 4 – keep it for minimal cross-compatibility. | Feature | Qt 4.8.7 | Qt 5/6 | |-----------------------|-------------------------------|-----------------------------| | Widgets module | QtGui | QtWidgets | | QString vs QByteArray | Less efficient Unicode | Better Unicode handling | | OpenGL | QGLWidget | QOpenGLWidget | | Threading | QThread (old style) | Better thread affinity | | Signals/slots | Macro-based (still works) | New syntax (function ptr) | | QML | Qt Quick 1.x (obsolete) | Qt Quick 2.x+ | | Platform plugins | X11, Windows, Cocoa (limited) | Wayland, Direct2D, etc. | 6. Debugging & Common Pitfalls Crash on modern Linux? Qt 4.8.7 uses X11 and older fontconfig. Set:

configure -platform win32-g++ -prefix C:\Qt\4.8.7 mingw32-make mingw32-make install main.cpp qt 4.8.7

#include <QApplication> #include <QLabel> int main(int argc, char *argv[]) TEMPLATE = app QT += core gui greaterThan(QT_MAJOR_VERSION,

export QT_X11_NO_MITSHM=1 export XLIB_SKIP_ARGB_VISUALS=1 QString str = "Hello"; QByteArray utf8 = str.toUtf8(); // correct // avoid: str.toAscii() or str.latin1() Missing std::sqrt or C++11 features Qt 4.8.7 expects C++98. Use qSqrt() from <QtGlobal> or #include <math.h> . No automatic high-DPI Use QApplication::setFont(QFont("Arial", 16)) or set environment variable: Debugging & Common Pitfalls Crash on modern Linux