unreferenced formal parameter

RIVOPICO

Hi why take this warnings. Message of warnings:
C:\Users\moh\Desktop\Demonio_3.0_src (1)\Demonio_3.0_src\src\servidor\main.cpp:29: warning: C4100: 'hPrevInstance' : unreferenced formal parameter

Code:

int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine,
                   int nCmdShow)
{
}

I think because i need to include some reference???

[Moved to C++ Gurus ~kshegunov]

kshegunov

This is the standard warning for when you declare a function parameter, but never use it. You can "fix" this by either not giving the parameter a name, or by using Q_UNUSED to suppress the warning by explicitly marking the parameter as unused. E.g:

int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int) //< Not using any of the parameters
{
}

or

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    Q_UNUSED(hPrevInstance); //< We are not going to use that parameter.
}

RIVOPICO

sorry i forget include this. i use parameters this is the code:
#include <QApplication>
#include "mainwindow.h"
#include <Windows.h>
#ifndef Q_WS_X11
#include <QtPlugin>
#endif

#ifdef _MSC_VER
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
int argc = 0;
char *argv[1];
#else
int main(int argc, char *argv[])
{
#endif
QApplication a(argc, argv);
MainWindow w;
return a.exec();
}

SGaist

Hi,

And again: why are you writing your main like that ? There's no need.

kshegunov

You should listen to what @SGaist's been saying in your other thread and not use WinMain at all, much less the preprocessor. Just create an ordinary C++ program and call the QApplication::exec function. That's all there's to it - no preprocessor magic, no WINAPI fossils:

#include <QApplication>
#include "mainwindow.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    MainWindow w;
    w.show();

    return a.exec();
}

RIVOPICO

i am trying to record my keyboard and mouse with winapi
https://msdn.microsoft.com/en-us/library/windows/desktop/ms644990(v=vs.85).aspx

kshegunov

@RIVOPICO said in unreferenced formal parameter:

i am trying to record my keyboard and mouse with winapi

If you mean to do that in your program, then there's a Qt way. If you mean to do that globally for the whole OS, don't. Hooks are a bad idea and are in the API mostly to facilitate debugging (or variants thereof). It can slow your system to a crawl.