When you are writing code with GCC on Windows, and you pass a callback to a Windows API function, your callback must have the __stdcall calling convention. Otherwise, something in a random part of your application quite distant from the callback will fail in a weird way and you will spend two days learning lots of things you never wanted to know about the internals of Windows when in fact you just needed to add one word to your callback definition.
Here’s a netlabel who put out mostly free releases of ambient and electroacoustic albums and EP’s, so you can relax after a hard day of banging your head against a wall and nerdrage.