问题
Can someone explain why my app crashes with the following error:
EXC_BAD_ACCESS(Code = 1, address= ...)
This crash occurs only in 64 bit devices. I am not able to figure it out.
- (NSString *)getIPAddress
{
NSString *address = nil;
struct ifaddrs *interfaces = NULL;
struct ifaddrs *temp_addr = NULL;
int success = 0;
// retrieve the current interfaces - returns 0 on success
success = getifaddrs(&interfaces);
if (success == 0)
{
// Loop through linked list of interfaces
temp_addr = interfaces;
while(temp_addr != NULL)
{
if(temp_addr->ifa_addr->sa_family == AF_INET)// crashes here
{
// Check if interface is en0 which is the wifi connection on the iPhone
if([[NSString stringWithUTF8String:temp_addr->ifa_name] isEqualToString:@"en0"])
{
// Get NSString from C String
address = [NSString stringWithUTF8String:inet_ntoa(((struct sockaddr_in *)temp_addr->ifa_addr)->sin_addr)]; // crash also here
}
}
temp_addr = temp_addr->ifa_next;
}
}
// Free memory
freeifaddrs(interfaces);
return address;
}
Thanks!
回答1:
According to the documentation:
The ifa_addr field references either the address of the interface or the link level address of the interface, if one exists, otherwise it is NULL. (The sa_family field of the ifa_addr field should be consulted to determine the format of the ifa_addr address.)
It is likely there is an interface on your 64-bit device that does not have the ifa_addr
field populated.
To fix your problem, check for a NULL ifa_addr
. I also recommend breaking out of the loop since you are finished once you find en0
.
...
while(temp_addr != NULL)
{
if(temp_addr->ifa_addr != NULL && temp_addr->ifa_addr->sa_family == AF_INET)
{
// Check if interface is en0 which is the wifi connection on the iPhone
if([[NSString stringWithUTF8String:temp_addr->ifa_name] isEqualToString:@"en0"])
{
// Get NSString from C String
address = [NSString stringWithUTF8String:inet_ntoa(((struct sockaddr_in *)temp_addr->ifa_addr)->sin_addr)];
break;
}
}
temp_addr = temp_addr->ifa_next;
}
...
来源:https://stackoverflow.com/questions/29676138/ioscrash-in-64-bit-device