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For iPhone Simulator iOS4.0+, NSInvocation doesn't handle exceptions well. I came across a workaround to use objc_msgSend. When I tried it for the below invocation as objc_msgSend(target_, [invocation selector]) and commenting out [invocation invoke] under createResponseFromInvocation() hangs. I tried different ways of calling obj_msgSend and didn't work.

 
- (NSInvocation *)createInvocationWithSelector:(SEL)selector
                                     signature:(NSMethodSignature *)method
                                     arguments:(NSDictionary *)arguments {
  NSInvocation *invocation
    = [NSInvocation invocationWithMethodSignature:method];
  [invocation setSelector:selector];
  [invocation setTarget:target_];

  if (arguments != nil) {
    if ([method numberOfArguments] > 2) {
      [invocation setArgument:&arguments atIndex:2];
    }
  }

  return invocation;
}

// Invoke the given invocation and create a response from it.
- (WDResponse *)createResponseFromInvocation:(NSInvocation *)invocation {
  WDResponse *response;

  @try {
    [invocation invoke];
    if ([[invocation methodSignature] methodReturnLength] == 0) {
      response = [WDResponse responseWithValue:nil];
    } else {
      id result;
      [invocation getReturnValue:&result];
      response = [WDResponse responseWithValue:result];
    }
  }
  @catch (NSException * e) {
    NSLog(@"Method invocation error: %@", e);
    response = [WDResponse responseWithError:e];
  }
  return response;
}
user511347
  • 33
  • 3

1 Answers1

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I found a solution by removing NSInvocation completely and calling objc_msgSend on the selector. This workaround helped in resolving all NSInvocation Exception handling.

user511347
  • 33
  • 3
  • How did you handle method arguments? I have the same problem, but the number of arguments is only know at runtime. NSInvocation makes this easy, but objc_msgSend doesn't. – drekka Oct 01 '11 at 07:07