QCoreApplication::exec()

[JonB]

One could debate whether this question belongs in C++ Gurus sub-forum, but here it is anyway.

What exactly does QCoreApplication::exec() do, and what does it wait for?

I start with a "minimal" Qt Creator Console Application:

#include <iostream>

#include <QCoreApplication>

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

    std::cout << "Hello world!" << std::endl;

    return a.exec();
}

I guess the a.exec() is waiting for quit() to be called, through a signal or similar? Not much else for a console application to wait for....

So if I want a really console-type Hello world program, which prints it and then exits, I might as well omit the a.exec() here? At the moment code does not use any Qt functionality; if it did, would failing to run QCoreApplication::exec() have any adverse effects, e.g. would some Qt things fail to get cleaned up properly?

[jsulm]

@JonB said in QCoreApplication::exec():

a.exec()

It starts the Qt event loop. If you do not need event loop do not call exec.

[JonB]

@jsulm Good to know there aren't any significant "gotchas" for this simple case, thanks.