ulCategory (ULONG) - input

Category of alert to unregister.

This value can be the core alert category or an extended alert category as defined below:

PRTALERT_CATEGORY_ALL - 0x00000000

Unregister for all alerts for the given alert handle. This will remove registration for all printer ports (even remote ones) for the alert handle.
PRTALERT_CATEGORY_ALL_CORE - 0x00000002
Unregister for all core alerts for the port.
PRTALERT_CATEGORY_ALL_EXT - 0x00000003
Unregister for all extended alerts for the port.
PRTALERT_CATEGORY_CORE - 0x00000001
Core alert category. This will remove registration for only those core alerts whose bits are set in ulType for the port.
PRTALERT_CATEGORY_EXT_MAX - 0x0000DFFF
End of the extended alert categories.
PRTALERT_CATEGORY_EXTENDED - 0x0000D000
Beginning of the extended alert categories. Protocol converters should limit the category range to between 0x0000D000 and 0x0000DFFFF.
If the protocol converter does not support the given category, ERROR_INVALID_CATEGORY(117) is returned.