API crash error

Question

I am using Apple's Reachability sample code to test network connectivity and receive change notifications ( Sample code to improve performance ).

I looked at some locks of my application. It seems that some failures are related to the Reachability / SystemConfiguration Reachablity API (see below). SCNetworkReachabilityGetFlags is used only in the Reachability class provided by Apple. Or am I misinterpreting the crash log?

Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x00000000, 0x00000000 Crashed Thread: 0 Thread 0 Crashed: 0 libSystem.B.dylib 0x00000e70 mach_msg_trap + 20 1 libSystem.B.dylib 0x00003354 mach_msg + 60 2 SystemConfiguration 0x0001f480 configopen + 168 3 SystemConfiguration 0x00004d08 SCDynamicStoreCreateWithOptions + 272 4 SystemConfiguration 0x00004e54 SCDynamicStoreCreate + 24 5 SystemConfiguration 0x00015244 updateReachabilityStoreInfo + 152 6 SystemConfiguration 0x00016f04 updateCommCenterStatus + 32 7 SystemConfiguration 0x00017678 checkAddress + 1368 8 SystemConfiguration 0x0001a260 __SCNetworkReachabilityGetFlags + 1992 9 SystemConfiguration 0x0001b00c rlsPerform + 132 10 CoreFoundation 0x00058266 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 8 11 CoreFoundation 0x00028692 __CFRunLoopDoSources0 + 214 12 CoreFoundation 0x00027f62 __CFRunLoopRun + 258 13 CoreFoundation 0x00027d74 CFRunLoopRunSpecific + 220 14 CoreFoundation 0x00027c82 CFRunLoopRunInMode + 54 15 GraphicsServices 0x00004e84 GSEventRunModal + 188 16 UIKit 0x00004f8c -[UIApplication _run] + 564 17 UIKit 0x000024cc UIApplicationMain + 964 18 MyApp 0x0000f80c main (main.m:21) 19 MyApp 0x0000f77c start + 44 

Answer 1

I was fortunate enough to just try to open a network connection. Then, if that fails, set the flag to try the latter and avoid “reachability”. Even if “reachability” passes at startup, it can disappear and disappear at any time.

Answer 2

Reach is one of the worst examples of Apple code examples.

Despite the fact that it is well aware of network connections, it is rather poor [read: hopeless] when indicating whether the host is accessible.

You can also directly associate a host with a host and catch a timeout failure.

Answer 3

just comment out the next line in Reachability.m, if there is one.

  [super init]; 

Answer 4

Use it in the first view controller. It's easy to get into trouble when used as a modal view or other derivatives.