Xcode 4.2 - declaration of '...' will not be visible outside of this function warning

I use Apple Reachability class from Apple Sample code Reachability

in Xcode 4.2 and new Apple 3.0 compiler I get warning in this class that

+ (Reachability*) reachabilityWithAddress: (cons开发者_高级运维t struct sockaddr_in*) hostAddress;

declaration of 'struct sockaddr_in' will not be visible outside of this function*

I am not good at classic C %) so I dont understand how I can fix this warning or may be I can ignore it at all.

Thx

---

Add #import <netinet/in.h> in Reachability.h to get away with this