Extension initialization

The runtime calls an extension initialization function on the native side. The runtime calls this initialization function once each time the application that uses the extension runs. Specifically, the runtime calls the initialization function the first time the extension calls ExtensionContext.createExtensionContext() for any context.

The function initializes data that all extension contexts can use. Define your extension initializer function with the signature of FREInitializer() .

For example:

void MyExtensionInitializer 
    (void** extDataToSet, FREContextInitializer* ctxInitializerToSet, 
     FREContextFinalizer* ctxFinalizerToSet) 
    extDataToSet = NULL;  // This example does not use any extension data. 
    *ctxInitializerToSet = &MyContextInitializer; 
    *ctxFinalizerToSet = &MyContextFinalizer; 

The FREInitializer() method that you define returns the following data to the runtime:

  • A pointer to the data that the runtime later passes to each new extension context. For example, if all extension contexts use the same utility library, this data can include a pointer to the library. This data is called the extension data .

    The extension data can be any data you choose. It can be a simple primitive data type, or a pointer to a structure you define. In this example, the pointer is NULL because the extension does not have a use for this data.

  • A pointer to the context initialization function. Each time the ActionScript side calls ExtensionContext.createExtensionContext() , the runtime calls an extension context initialization function that you provide. See FREContextInitializer() .

  • A pointer to the context finalizer function. The runtime calls this function when the runtime disposes of the extension context. This call occurs when the ActionScript side calls the ExtensionContext instance’s dispose() method. If dispose() is not called, the runtime garbage collects the ExtensionContext instance. See FREContextFinalizer() .

For application-bundled extensions, your implementation of FREInitializer() can have any name. Specify the name of the initialization function in the extension descriptor file. See Native extension descriptor files .

For device-bundled applications, how to specify the extension initializer function is device-dependent.

The following sequence diagram shows the AIR runtime calling the FREInitializer() function. It also shows context initialization. For more information, see Extension context initialization .

View full size graphic
Extension initialization sequence

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