Inside Macintosh: QuickDraw GX Printing Extensions and Drivers /

Chapter 4 - Printing Messages / Printing Messages Reference

Printing Messages / Storage Messages

GXShutDown

QuickDraw GX sends the GXShutDown message at the end of a print job. You can override the GXShutDown message to clean up or dispose of any private storage you allocated in your override of the GXInitialize message. Your override of the Shutdown message must match the following formal declaration:

OSErr MyShutDown (void);

function result

An error code. The value noErr indicates that the operation was successful.

DESCRIPTION

QuickDraw GX sends the GXShutDown message after a print job is complete. The printing context still exists when this message is sent.

You need to override this message to deallocate any storage you were using within the context of the print job and deallocate the handle you placed into the context as a result of the GXInitialize message. The GXShutDown message is always the last message a message handler receives before it is removed from the message chain.

The default implementation of the GXShutDown message deallocates memory that was allocated by the printing system.

SPECIAL CONSIDERATIONS

You need to override the GXShutDown message and deallocate storage if you have also overridden the GXInitialize message.

You never send the GXShutDown message yourself.

You never forward the GXShutDown message to other message handlers.

RESULT CODES

gxSegmentLoadFailedErr	A required code segment could not be found, or there was not enough memory to load it.
gxPrUserAbortErr	The user has canceled printing.
memFullErr	There is not enough memory to retrieve the tagged data.
resNotFound	The specified data could not be found.

SEE ALSO

You can find examples of overrides of the GXShutDown message in Listing 2-18 on page 2-31 in the chapter "Printing Extensions" and in Listing 3-18 on page 3-48 in the chapter "Printer Drivers."

The GXInitialize message is described in the previous section.

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