const char* utf8String = [binaryString UTF8String];
const char* endPtr = NULL;
long int foo = strtol(utf8String, &endPtr, 2);
if (endPtr != utf8String + strlen(utf8String))
{
// string wasn't entirely a binary number
}
if (errno == ERANGE && (foo == LONG_MAX || foo == LONG_MIN))
{
// number was too big or too small
}