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
.
