Question

I need to send a distributed notification from my cocoa app to my firebreath project, so I need to create an observer and a selector in my firebreath code.
I changed the class extension to “.mm” in order to support objective-c code. I already have objective-c code in my firebreath project and is working ok. But when I try to create an observer I get errors in my code and I don’t know how to resolve it.

Here is my source code from firebreath project:

//This is the selector 
- (void)receiveAppConfirmationNotification:(NSNotification*)notif{
    //The application is alive.
    NSLog(@"The application is alive!!!!!!!!");
}

std::string MyProjectAPI::bgp(const std::string& val)
{       
    //Add an observer to see if the application is alive.
    NSString *observedObject = @"com.test.net";
    NSDistributedNotificationCenter *center = [NSDistributedNotificationCenter defaultCenter];
    [center addObserver: self
               selector: @selector(receiveAppConfirmationNotification:)
                   name: @"App Confirmation Notification"
                 object: observedObject];
}

Here are my errors:

…firebreath/../projects/MyProject/MyProjectAPI.mm:133: error: expected unqualified-id before ‘-‘ token. This is the line where I defined the “receiveAppConfirmationNotification” method.

…firebreath/../projects/MyProject/MyProjectAPI.mm:157: error: ‘self’ was not declared in this scope.

How can I do to define the selector?
How can I do to add the observer as the class itself?

Answer 1

A selector has to be part of an objective-c++ class; you can’t just throw it in the middle of nowhere there, it should be in the @implementation section of the class.

To keep things as compatible as possible, I recommend putting both @interface and @implementation sections in the .mm file so that the .h file is compatible with C++, but that’s up to you; it’ll just be easier if you do it that way. You can use the pimpl pattern to help with this if you want.