XTYP_ADVSTART

A client uses the XTYP_ADVSTART transaction to establish an advise loop with a server. A DDE server callback function, DdeCallback, receives this transaction when a client specifies XTYP_ADVSTART as the uType parameter of the DdeClientTransaction function.

HDDEDATA CALLBACK DdeCallback(
  UINT uType,     // XTYP_ADVSTART
  UINT uFmt,      // clipboard data format
  HCONV hconv,    // handle to the conversation
  HSZ hsz1,       // handle to a string
  HSZ hsz2,       // handle to a string
  HDDEDATA hdata, // handle to a global memory object
  DWORD dwData1,  // transaction-specific data
  DWORD dwData2   // transaction-specific data
);

Parameters

uType

Specifies the transaction type.

uFmt

Specifies the data format requested by the client.

hconv

Handle to the conversation.

hsz1

Handle to the topic name.

hsz2

Handle to the item name.

hdata

Not used.

dwData1

Not used.

dwData2

Not used.

Return Values

A server callback function should return TRUE to allow an advise loop on the specified topic name and item name pair, or FALSE to deny the advise loop. If the callback function returns TRUE, any subsequent calls to the DdePostAdvise function by the server on the same topic name and item name pair causes the system to send XTYP_ADVREQ transactions to the server.

Remarks

If a client requests an advise loop on a topic name, item name, and data format for an advise loop that is already established, the Dynamic Data Exchange Management Library (DDEML) does not create a duplicate advise loop but instead alters the advise loop flags (XTYPF_ACKREQ and XTYPF_NODATA) to match the latest request.

This transaction is filtered if the server application specified the CBF_FAIL_ADVISES flag in the DdeInitialize function.

Requirements

  Windows NT/2000: Requires Windows NT 3.1 or later.
  Windows 95/98: Requires Windows 95 or later.
  Header: Declared in Ddeml.h; include Windows.h.

See Also

Dynamic Data Exchange Management Library Overview, Dynamic Data Exchange Management Transactions, DdeClientTransaction, DdeInitialize, DdePostAdvise