How to implement sqlite3_trace callback in objective c

I'm having trouble implementing following callback from the sqlite3 api. Has someone a good 开发者_运维百科example for implementing callbacks like this?

void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);

Found the solution: (this goes before @implementation block)

void myCallbackFunc(void *foo, const char* bar) {
    NSLog(@"=> %s", bar);
}

Essentially, implement a function with the following signature:

void (*xTrace)(void*,const char*);

and then place a pointer to this function in the call to sqlite3_trace. The sqlite3_trace page tells you what values will be passed to this function, so that you can NSLog then, [fs]printf them, show them on the screen, whatever you would like