"No previous prototype for function" warning

Question

i use shareKit to myself program .

but in the FBConnectGlobal, there are some warning,

NSMutableArray* FBCreateNonRetainingArray() {
  CFArrayCallBacks callbacks = kCFTypeArrayCallBacks;
  callbacks.retain = RetainNoOp;
  callbacks.release = ReleaseNoOp;
  return (NSMutableArray*)CFArrayCreateMutable(nil, 0, &callbacks);
}

like this method, it warning:"No previous prototype for function FBCreateNonRetainingArray"

Answer 1

According to c standard, declaring the prototype as

NSMutableArray* FBCreateNonRetainingArray(void);
//      --------------->                  ^^^^   
// Yes, with the void as the parameter

solves the issue.

Answer 2

To clarify Eric Dchao's answer above, someone at facebook apparently didn't put a "static" in front of that BOOL?

Anyways, changing from this

BOOL FBIsDeviceIPad() {
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 30200
  if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
    return YES;
  }
#endif
  return NO;
}

to this

static BOOL FBIsDeviceIPad() {
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 30200
  if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
    return YES;
  }
#endif
  return NO;
}

fixed it for me.

Answer 3

UPDATE: Disable warnings is not a good solution, check @Derek Bredensteiner's answer.

In Xcode 4, go to your project's Build Settings. Search for "prototype". There should be an option called "Missing Function Prototypes"; disable it.

via here