Question

I tried to use Windows api PageSetupDlg in Qt to save some time. However, I get errors during compilation in the title. Here is my code:

#include <QtCore/QCoreApplication>
#include <windows.h>
#include <QDebug>

int main(int argc, char *argv[])
{
    PAGESETUPDLG lppsd;
    QCoreApplication a(argc, argv);
//#ifdef Q_WS_WIN
//    MessageBox(NULL,TEXT("This is windows window"),
//               TEXT("HAHAYOYO"),MB_OK);
    PageSetupDlg(&lppsd);
//#endif
    return a.exec();
}

I ‘ve added the LIBS += -LC:\Windows\System32\ComDlg32.dll in the .pro file, however it doesn’t work. I’m not sure whether it is correct to write like that.

My second question is that do I need to add the #ifdef & #endif statements when I try to call a Windows API function? Since the MessageBox function runs correctly without them.

Answer 1

you need to add Comdlg32.lib, not ComDlg32.dll which is a dll, not an include library.
Though why not just use QPrintDialog? Also, you need to initialize the PAGESETUPDLG variable if you plan on using it, see this.

My second question is that do I need to add the #ifdef & #endif statements when I try to call a Windows API function?

You should add them, if you intend on running on a non-Windows system, the WinAPI will most certainly not be available (and cause of this you should use QMessageBox), however, if you system is dependant on WinAPI functions, then there is no point, because you’ll be bound to Windows regardless.