ios – A operate declaration and not using a prototype is deprecated in all variations of C

I’m utilizing Firebase Analytics on my pod file of an iOS challenge. I get the next errors once I run the app.

A operate declaration and not using a prototype is deprecated in all variations of C

it is proven on the next code:

GDTCORNetworkType GDTCORNetworkTypeMessage() {.  <----error right here
#if !TARGET_OS_WATCH
  SCNetworkReachabilityFlags reachabilityFlags = [GDTCORReachability currentFlags];
  if ((reachabilityFlags & kSCNetworkReachabilityFlagsReachable) ==
      kSCNetworkReachabilityFlagsReachable) {
    if (GDTCORReachabilityFlagsContainWWAN(reachabilityFlags)) {
      return GDTCORNetworkTypeMobile;
    } else {
      return GDTCORNetworkTypeWIFI;
    }
  }
#endif
  return GDTCORNetworkTypeUNKNOWN;
}

I attempted doing a pod replace however I am nonetheless unable to repair the issue.