XTYP_ADVREQ transaction

The XTYP_ADVREQ transaction informs the server that an advise transaction is outstanding on the specified topic name and item name pair and that data corresponding to the topic name and item name pair has changed. The system sends this transaction to the Dynamic Data Exchange (DDE) callback function, DdeCallback, after the server calls the DdePostAdvise function.

#define     XCLASS_DATA              0x2000
#define     XTYPF_NOBLOCK            0x0002
#define     XTYP_ADVREQ             (0x0020 | XCLASS_DATA | XTYPF_NOBLOCK )

Parameters

uType

The transaction type.

uFmt

The format in which the data should be submitted to the client.

hconv

A handle to the conversation.

hsz1

A handle to the topic name.

hsz2

A handle to the item name that has changed.

hdata

Not used.

dwData1

The count, in the low-order word, of XTYP_ADVREQ transactions that remain to be processed on the same topic, item, and format name set within the context of the current call to the DdePostAdvise function. The count is zero if the current XTYP_ADVREQ transaction is the last one. A server can use this count to determine whether to create an HDATA_APPOWNED data handle to the advise data.

The low-order word is set to CADV_LATEACK if the DDEML issued the XTYP_ADVREQ transaction because of a late-arriving DDE_ACK message from a client being outrun by the server.

The high-order word is not used.

dwData2

Not used.

Return value

The server should first call the DdeCreateDataHandle function to create a data handle that identifies the changed data and then return the handle. The server should return NULL if it is unable to complete the transaction.

Remarks

A server cannot block this transaction type; the CBR_BLOCK return code is ignored.

Requirements

See also

Reference

DdeCreateDataHandle

DdeInitialize

DdePostAdvise

Conceptual

Dynamic Data Exchange Management Library