Syntax

  LONG MM_ObjectIO ( 
     HNDL  *messageHandle, 
     HNDL   reservationHandle, 
     LONG   function, 
     LONG   parameter1, 
     LONG   parameter2, 
     LONG   parameter3, 
     LONG   bufferLength, 
     void   buffer, 
     LONG   requestToken, 
     void ( *callbackRoutine )( 
        LONG   requestHandle, 
        LONG   applicationRequestToken, 
        LONG   returnParameter, 
        LONG  completionCode ) ); 
  
  

Parameters

*messageHandle

Points to a HNDL where the Media Manager will copy the messageHandle associated with this request.

reservationHandle

Identifies the reserved IO object. It is obtained by calling MM_ReserveIOObject.

function

Indicates which IO function is to be performed. For a list of applicable functions, see IO Function Operations.

Parameter1

Defined by the IO function.

Parameter2

Defined by the IO function.

Parameter3

Defined by the IO function.

BufferLength

Defined by the IO function.

buffer

Defined by the IO function.

requestToken

The value of this parameter is defined by the application making this function call. It is returned to the application by the callbackRoutine.

callbackRoutine

Points to a non-blocking callback routine that the Media Manager calls during the completion of the I/O request. Its parameters are as follows:

MessageHandle

The same message handle as given by the output parameter messageHandle for MM_ObjectIO.

requestToken

The same request token passed to MM_ObjectIO.

returnParameter

An IO function-specific return parameter. This is valid only if the request was successful, i.e., completionCode equals MM_OK. Note that many of the IO functions do not return a value in returnParameter.

completionCode

The value indicates the results of the IO request. MM_OK indicates a successful completion. All other values indicate a failure.

Return Values

The following table lists return values and descriptions.

Remarks

It is possible for the callbackRoutine to be called prior to returning from MM_ObjectIO. The application submitting an IO request through MM_ObjectIO can abort the request by passing the value in messageHandle to MM_AbortRequest. IO requests can be aborted only prior to callbackRoutine being called.

See Also

• IO Function Operations
• Return Values
• Reservation Modes