my project was buied in os 3.0
but now i want to do some changes with os 4.
so when i run my project in xcode 3.2.4.
i get those errors......
ld: warning: in /Users/abc/SystemConfiguration.framework/SystemConfiguration, missing required architecture i386 in file ld: warning: in /Users/abc/libz.1.2.3.dylib, missing required architecture i386 in file Undefined symbols: "_SCNetworkReachabilityScheduleWithRunLoop", referenced from: -[ReachabilityQuery startListeningForReachabilityChanges:onRunLoop:] in Reachability.o "_SCNetworkReachabilityGetFlags", referenced from: -[Reachability remoteHostStatus] in Reachability.o -[Reachability isHostReachable:] in Reachability.o -[Reachability isNetworkAvailableFlags:] in Reachability.o -[Reachability isAdHocWiFiNetworkAvailableFlags:] in Reachability.o "_SCNetworkReachabilityCreateWithAddress", referenced from: -[Reachability reachabilityRefForAddress:] in Reachability.o -[Reachability isNetworkAvailableFlags:] in Reachability.o -[Reachability isAdHocWiFiNetworkAvailableFlags:] in Reachability.o "_SCNetworkReachabilityUnscheduleFromRunLoop", referenced from: -[Reachability stopListeningForReachabilityChanges] in Reachability.o "_SCNetworkReachabilityCreateWithName", referenced from: -[Reachability reachabilityRefForHostName:] in Reachability.o -[Reachability isHostReachable:] in Reachability.o "_SCNetworkReachabilitySetCallback", referenced from: -[ReachabilityQuery startListeningForReachabilityChanges:onRunLoop:] in Reachability.o ld: symbol(s) not found collect2: ld returned 1 exit status