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Print spooler support for printer Directory Services

  • Artikkeli

Print spooler support for Directory Services consists of:

  • Publishing print queues

  • Maintaining three registry keys

  • Allowing access to spooler-maintained registry keys

  • Returning a print queue's publication state

Publishing print queues

The SetPrinter function allows callers to publish, unpublish, or update a print queue object. For these purposes, the SetPrinter function must be called with an input structure of PRINTER_INFO_7.

A print queue object can be published only if it is associated with the computer object describing the print server to which the user is connected. A user's ability to publish a print queue is determined by their access rights, as contained in the user's client security context. You can publish a print queue if you have Manage Printers permission on the print queue.

Maintaining three registry keys

Three registry keys contain copies of all information published in the print queue object. The three keys are referenced using the following identifiers, defined in winspool.h:

Key Definition
SPLDS_DRIVER_KEY For storing driver-specific information, which can be supplied by the spooler or the driver.
SPLDS_SPOOLER_KEY For storing spooler-supplied, spooler-specific information.
SPLDS_USER_KEY For storing application-supplied, user-specific information.

The spooler uses SPLDS_DRIVER_KEY to store driver capabilities that can be obtained by calling the DeviceCapabilities function. The driver is responsible for storing driver capabilities that the spooler cannot obtain, as described in Printer driver support for printer Directory Services. Values stored under these keys must be identified by SPLDS_-prefixed constants, defined in winspool.h.

The spooler keeps track of which values under these keys have been modified since the last time the print queue object was updated. Each time the spooler publishes or updates the print queue object, it copies all modified values into the object.

Allowing access to spooler-maintained registry keys

The spooler allows printer drivers to access the three spooler-maintained registry keys by calling the SetPrinterDataEx, GetPrinterDataEx and EnumPrinterDataEx functions. The SetPrinterDataEx function sets values under the keys, while GetPrinterDataEx and EnumPrinterDataEx return current values. Drivers should not set values under the SPLDS_SPOOLER_KEY key. Callers of these functions do not specify a complete registry path; the functions automatically determine the path to the specified print queue's registry entries.

Returning a print queue's publication state

The GetPrinter function allows callers to determine if a print queue is currently published. For this purpose, the GetPrinter function must be called with an input structure of PRINTER_INFO_7. The function returns the print queue's publication state (published or unpublished) and object identifier.