Legacy Document

Inside Macintosh: More Macintosh Toolbox /

Chapter 6 - Component Manager / Component Manager Reference

Routines for Components / Dispatching to Component Routines

CallComponentFunctionWithStorage

The CallComponentFunctionWithStorage function invokes a specified function
of your component with the parameters originally provided by the application that called your component. You pass these parameters by specifying the same component parameters record that was received by your component's main entry point. The CallComponentFunctionWithStorage function also provides a handle to the memory associated with the current connection.

FUNCTION CallComponentFunctionWithStorage 
               (storage: Handle; params: ComponentParameters;
                func: ComponentFunction): LongInt;

storage

A handle to the memory associated with the current connection. The Component Manager provides this handle to your component along with the request.

params

The component parameters record that your component received from the Component Manager.

func

The address of the function that is to handle the request. The Component Manager calls the routine referred to by the func parameter as a Pascal function with the parameters that were originally provided by the application. These parameters are preceded by a handle to the memory associated with the current connection. The routine referred to by the func parameter must return a function result of type ComponentResult (a long integer) indicating the success or failure of the operation.

DESCRIPTION

The CallComponentFunctionWithStorage function returns the value that is returned by the function referred to by the func parameter. Your component should use this value to set the current error for this connection.

SPECIAL CONSIDERATIONS

CallComponentFunctionWithStorage takes as a parameter a handle to the memory associated with the connection, so subroutines of a component that don't need global data should use the CallComponentFunction routine described in the previous section instead.

If your component subroutine requires a handle to the memory associated with the connection, you must use CallComponentFunctionWithStorage. You allocate the memory for a given connection each time your component is opened. You inform the Component Manager that a connection has memory associated with it by calling the SetComponentInstanceStorage procedure.

SEE ALSO

For an example that uses CallComponentFunctionWithStorage,
see Listing 6-5 on page 6-16. Use the SetComponentInstanceError procedure, described on page 6-67, to set the current error for a connection. A description of the SetComponentInstanceStorage procedure is given next.