Intermec 6200 Reference Guide

R

Once the drivers are loaded as defined in the preceding paragraphs, no special

processing by the application is needed.  This makes it possible for offĆtheĆshelf

packages to take advantage of the IrDA protocol.  In this mode, all

printerĆrelated errors are handled by the IrDA driver.  A message is displayed

and the user has the ability to Cancel or Retry.  If the user selects Retry, the

driver attempts to continue printing.  If the user selects Cancel, the driver

attempts to clean up.  The standard Windows API returns a standard error,

indicating that a problem occurred.  This is the application's signal to abort the

print job.

In this mode, the application can link to the IrDA driver in the same manner

that it would link to any Windows DLL.  Once linked, the application can use the

driver's API to perform various operations.  The application registers a callback

with the driver. The application needs to perform the following actions to define

a new error handler:

1. Link to driver and obtain 

PrtService

 entry point.

2. Call 

PrtService

 to enable the driver, using 

PRT_ENABLE (0x0001)

.

3. Call 

PrtService

 to register the new handler, using 

PRT_SETPROC (0x0010)

and the address of the new handler.  The new handler should have the

following prototype:

extern “C” WORD _export FAR PASCAL ShowPrtError( WORD wCurErr )

This callback is called for each error and must return 

IDCANCEL (0x02),

IDRETRY (0x04)

 or 

0

.  If the application returns 

0

, the default handler proĆ

cesses the error.  For consistency, the application should handle all the erĆ

rors.  Use any method for displaying the message you want.  Make your

dialog model, if possible.  Remember that, depending on the method of disĆ

playing the message, you may need to translate the return values into 

ID-

CANCEL

 or 

IDRETRY

 so the printer driver knows how to deal with it.  See the

Error Codes and Messages topic, on page 3Ć41, for the various error condiĆ

tions that can occur.

4. Perform normal printing operations.
5. Call 

PrtService

 to remove the error handler, using 

PRT_SETPROC (0x0010)

and a 

NULL

 value for the handler address.

6. Call

 

PrtService

 to disable the driver, using

 

PRT_DISABLE (0x0002)

.

See the Printer Services API topic, below, for more information about available

printer services.

The IrDA printer driver includes an API to provide access to the features of the

IrDA driver that are not available through the standard Windows API.