Running a QT application from Command promt in WIndows

Question

I have made a small QT application and i am trying to run it thru command prompt on Windows:

#include <QMainWindow>
#include <QLabel>

int main(int argc,char* argv[])
{
    QMainWindow a(argc,argv)
    QLabel *NewLabel = new QLabel("Hi i am a label");
    NewLabel->show();
    return a.exec();
}

after doing qmake -project and then qmake -TestPrg.pro then i try make,here it fails with following error:

D:\TestPrg>make
make -f Makefile.Debug
make[1]: Entering directory `D:/TestPrg'
Makefile.Debug:58: *** missing separator.  Stop.
make[1]: Leaving directory `D:/TestPrg'
make: *** [debug] Error 2

If we look at makefile.debug ,line number 58 and add a TAB before "<<",it complains at someother line number.So i feel there is something wrong in the compiler options ,can someone guide how to make it working.

Thanks alot

Answer 1

I have just made an example work on my machine. The code goes below, but you have at least a few mistakes, namely:

• You use QMainWindow for being the application as it seems as opposed to QApplication. That is not going to compile.

• Respectively, you would need to include QApplication rather than QMainWindow.

• You miss a semi-colon after the first statement in the main function.

• You construct a QLabel on the heap needlessly. In this particular scenario, it could be a simple stack object.

• You use invoking qmake as qmake -foo rather than just qmake or make foo.

• You are trying to use "make" in the Windows Command prompt as opposed to nmake or jom. If you use Visual Studio and MSVC, do not mix it with mingw, cygwin and other things. Just use nmake, otherwise, yes, use make for the latter options.

main.cpp

#include <QApplication>
#include <QLabel>

int main(int argc, char **argv)
{
    QApplication a(argc, argv);
    QLabel NewLabel("Hi i am a label");
    NewLabel.show();
    return a.exec();
}

main.pro

TEMPLATE = app
TARGET = main
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
SOURCES += main.cpp

Build and Run

* qmake
* nmake
* main.exe