qtimer in console application

[wysota]

Why crashing?? What am I doing wrong?

Ask your debugger. It's likely you run out of memory as you probably need twice as much memory as the file you are copying.

I need to copy several files into one. I don't think I can use QFile::copy() for that, can i?

It depends if you limit yourself to asking this question or if you look at how the method is implemented and do something similar.