NSPLookupServiceNext

A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

This function is called after obtaining a handle from a previous call to NSPLookupServiceBegin in order to retrieve the requested service information.

The provider will pass back a WSAQUERYSET structure in the lpqsResults buffer. The client should continue to call this function until it returns WSA_E_NOMORE, indicating that all the WSAQUERYSET have been returned.

Syntax

int NSPAPI WSALookupServiceNext(
  HANDLE hLookup,
  DWORD dwControlFlags,
  LPDWORD lpdwBufferLength,
  LPWSAQUERYSET lpqsResults 
);

Parameters

• hLookup
  [in] Handle returned from the previous call to WSALookupServiceBegin.

• dwControlFlags
  [in] Flags to control the next operation. Currently only LUP_FLUSHPREVIOUS is defined as a means to cope with a result set that is too large. If an application does not supply a large enough buffer, setting LUP_FLUSHPREVIOUS instructs the provider to discard the last result set, which was too large, and move to the next set for this call.

• lpdwBufferLength
  [in, out] On input, the number of bytes contained in the buffer pointed to by lpqsResults. On output, if the function fails and the error is WSAEFAULT, then it contains the minimum number of bytes to pass for the lpqsResults to retrieve the record.

• lpqsResults
  [out] Pointer to a block of memory that will contain one result set in a WSAQUERYSET structure on return.

Return Value

The function should return NO_ERROR (zero) if the routine succeeds. It should return SOCKET_ERROR (–1) if the routine fails and it must set the appropriate error code using SetLastError.

The following table shows the possible error codes.

Remarks

The dwControlFlags specified in this function and the ones specified at the time of NSPLookupServiceBegin are treated as "restrictions" for the purpose of combination. The restrictions are combined between the ones at NSPLookupServiceBegin time and the ones at NSPLookupServiceNext time. Therefore, the flags at NSPLookupServiceNext can never increase the amount of data returned beyond what was requested at NSPLookupServiceBegin, although it is not an error to specify more or less flags. The flags specified at a given NSPLookupServiceNext apply only to that call.

The dwControlFlags LUP_FLUSHPREVIOUS and LUP_RES_SERVICE are exceptions to the combined restrictions rule because they are behavior flags instead of restriction flags. If either of these flags is used in NSPLookupServiceNext, they have their defined effect regardless of the setting of the same flags at NSPLookupServiceBegin.

For example, if LUP_RETURN_VERSION is specified at NSPLookupServiceBegin, the service provider retrieves records including the version. If LUP_RETURN_VERSION is not specified at NSPLookupServiceNext, the returned information does not include the version, even though it was available. No error is generated.

Also for example, if LUP_RETURN_BLOB is not specified at NSPLookupServiceBegin but is specified at NSPLookupServiceNext, the returned information does not include the private data. No error is generated.

The following table describes how the query results are represented in the WSAQUERYSET structure.

Requirements

See Also

Reference

WSAQUERYSET (Windows Sockets)
NSPLookupServiceBegin