What does 'void (*return_socket)(void *closure);' mean?

Question

I am browsing though the XCB sources and I found this weird struct member:

void (*return_socket)(void *closure);

What does that mean? What's another way to write this?

Answer 1

That is a function pointer. It points to a function that returns void and receives a void * as parameter.

For example, you could use that as:

void myFunction(void *closure)
{
    printf("myFunction called with closure=%p", closure);
}

void (*return_socket)(void *closure) = myFunction;