WPUQueryBlockingCallback (Compact 2013)

3/26/2014

This function returns a pointer to a callback function the service provider should invoke periodically while servicing blocking operations.

Syntax

int WPUQueryBlockingCallback(
  DWORD dwCatalogEntryId,
  LPBLOCKINGCALLBACK FAR* lplpfnCallback,
  PDWORD_PTR lpdwContext,
  LPINT lpErrno 
);

Parameters

• dwCatalogEntryId
  [in] Descriptor identifying the calling service provider.

• lplpfnCallback
  [out] Pointer that receives the blocking callback function.

• lpdwContext
  [out] Pointer that receives a context value that the service provider must pass into the blocking callback.

• lpErrno
  [out] Pointer to the error code.

Return Value

If no error occurs, this function returns zero and stores a pointer to a blocking callback function in lpfnCallback and an associated context value in lpdwContext. Otherwise, it returns SOCKET_ERROR, and a specific error code is available in lpErrno.

This function always returns NULL in lpfnCallback in Windows Embedded Compact.

The following table shows possible error codes.

Remarks

This function returns a pointer to a callback function in lpfnCallback to be invoked periodically during blocking operations. This function also returns a context value in lpdwContext to be passed into the blocking callback.

Using Win32, this function can return NULL in lpfnCallback, indicating that no user defined-blocking hook is installed. In this case, the service provider should use the native Win32 synchronization objects to implement blocking.

LPBLOCKINGCALLBACK is defined as typedef BOOL ( CALLBACK FAR * LPBLOCKINGCALLBACK )( DWORD dwContext );.

The blocking callback will return TRUE if the service provider is to continue waiting for the blocking operation to complete.

Any missing parts of the address will default to a reasonable value, if possible. For example, a missing port number will default to zero.

Requirements

See Also

Reference

Winsock SPI Functions