Simple Qt App refuses to compile once a signal/slot is added

Question

So basically, I am making a very simple Qt app to help me along as I learn OpenGL. The idea
is that I have two windows, one is a GL context (GLWidget, derived from QGLWidget) and the other is a simple GUI with a couple of progress bars and a text area.

I can get the app to compile and run, and everything is beautiful UNTIL I tried to connect signals and slot between the two windows. I have read through the docs on QGLWidget, the official tutorial on signals and slots, and the documentation for int connect().

To illustrate: my main.cpp file:

#include <QApplication>
#include <QObject>

#include "glwidget.h"
#include "mainwindow.h"

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

    MainWindow *mWindow = new MainWindow();
    GLWidget *gl = new GLWidget();

    //If this line is commented out, the program compiles and runs
    connect(gl, SIGNAL(fpsReport(float)), mWindow, SLOT(updateFPS(float));

    mWindow->show();
    gl->show();

    return app.exec();
}

The specific compiler errors I am getting are:

In function 'int qMain(int, char**)':
invalid conversion from 'GLWidget*' to 'SOCKET'
cannot convert 'const char*' to 'const sockaddr*' for argument '2' to 'int
connect(SOCKET, const sockaddr*, int)'

Not sure if this is relevant, but I'm using Qt Creator 2.0.1, based on Qt 4.7.0 (32 bit). Running 32-bit Windows 7 Ultimate.

Answer 1

connect is a static member of QObject. When used outside of a QObject context, you need to specify the scope as such :

QObject::connect(gl, SIGNAL(fpsReport(float)), mWindow, SLOT(updateFPS(float));

Otherwise, the compiler tries to call another function called connect() which resides in the global scope, and obviously, this other function uses different parameters.