4.22 WFSSetBlockingHook

HRESULT WFSSetBlockingHook( lpBlockFunc, lppPrevFunc )

Establishes an application-specific blocking routine.

Parameters XFSBLOCKINGHOOK lpBlockFunc

Pointer to the procedure instance address of the blocking routine to be installed.

LPXFSBLOCKINGHOOK lppPrevFunc

Returned pointer to a pointer to the procedure instance of the previously installed blocking routine.

Mode Immediate

Comments When this function is successfully issued by an application, it returns a pointer to the previously installed blocking routine. The application may save this pointer so that it can be restored if desired. If such “nesting” is not required, the application can discard this value and simply use the WFSUnhookBlockingHook function to restore the default routine at any time.

See Section 3.12 for a complete discussion.

Error Codes If the function return is not WFS_SUCCESS, it is one of the following error conditions:

WFS_ERR_INTERNAL_ERROR

An internal inconsistency or other unexpected error occurred in the WOSA/XFS subsystem.

WFS_ERR_NOT_STARTED

The application has not previously performed a successful WFSStartUp.

WFS_ERR_OP_IN_PROGRESS

A blocking operation is in progress on the thread; only WFSCancelBlockingCall and WFSIsBlocking are permitted at this time.

WFS_ERR_INVALID_POINTER

A pointer parameter does not point to accessible memory.

See also WFSUnhookBlockingHook, WFSCancelBlockingCall, WFSIsBlocking