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DIFXAPILOGCALLBACK routine

A DIFXAPILOGCALLBACK-typed function is an application-supplied callback function that an application registers with DIFxAPI by calling DIFXAPISetLogCallback. DIFxAPI calls the callback function to log events that occur during DIFxAPI operation.

Syntax

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void (__cdecl* DIFXAPILOGCALLBACK) DIFXAPILOGCALLBACK;

void DIFXAPILOGCALLBACK(
  DIFXAPI_LOG EventType,
  DWORD Error,
  PCTSTR EventDescription,
  PVOID CallbackContext
)
{ ... }

Parameters

EventType

A DIFXAPI_LOG-typed enumerator that indicates the event type. The DIFXAPI_LOG enumeration is defined as follows:

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typedef enum {
  DIFXAPI_SUCCESS,
  DIFXAPI_INFO,
  DIFXAPI_WARNING,
  DIFXAPI_ERROR
} DIFXAPI_LOG;

The enumeration values represent the event types that are listed in the following table.

Value	Event type
DIFXAPI_SUCCESS	A success event that logs a message that indicates an operation succeeded.
DIFXAPI_INFO	An information event that logs a message that describes the context or progress of an operation.
DIFXAPI_WARNING	A warning event that logs a message about a possible problem that is not a fatal error.
DIFXAPI_ERROR	An error event that logs a message about a fatal error.

Error

A DWORD value that specifies a Microsoft Win32 error code that is associated with an event, if one exists; otherwise, Error is zero.

EventDescription

A pointer to a NULL-terminated string that describes the event.

CallbackContext

A pointer to the callback context that a caller set for the callback function.

Return value

None

Remarks

To register a DIFxAPI log callback function, an application calls DIFXAPISetLogCallback and supplies a pointer to an application-supplied DIFXAPILOGCALLBACK-typed function and a pointer to an optional application-specific callback context.

For more information about DIFxAPI event logging, see Using DIFxAPI Event Logging.

Requirements