XTYP_WILDCONNECT

The XTYP_WILDCONNECT transaction allows a client to establish a conversation on each of the server's service name and topic name pairs that match the specified service name and topic name. A DDE server callback function, DdeCallback, receives this transaction when a client specifies a NULL service name, a NULL topic name, or both in a call to the DdeConnect or DdeConnectList function.

HDDEDATA CALLBACK DdeCallback(
  UINT uType,     // XTYP_WILDCONNECT
  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

Not used.

hconv

Not used.

hsz1

Handle to the topic name. If this parameter is NULL, the client is requesting a conversation on all topic names that the server supports.

hsz2

Handle to the service name. If this parameter is NULL, the client is requesting a conversation on all service names that the server supports.

hdata

Not used.

dwData1

Pointer to a CONVCONTEXT structure that contains context information for the conversation. If the client is not a Dynamic Data Exchange Management Library (DDEML) application, this parameter is set to 0.

dwData2

Specifies whether the client is the same application instance as the server. If the parameter is 1, the client is same instance. If the parameter is 0, the client is a different instance.

Return Values

The server should return a data handle that identifies an array of HSZPAIR structures. The array should contain one structure for each service-name and topic-name pair that matches the service-name and topic-name pair requested by the client. The array must be terminated by a NULL string handle. The system sends the XTYP_CONNECT_CONFIRM transaction to the server to confirm each conversation and to pass the conversation handles to the server. The server will not receive these confirmations if it specified the CBF_SKIP_CONNECT_CONFIRMS flag in the DdeInitialize function.

The server should return NULL to refuse the XTYP_WILDCONNECT transaction.

Remarks

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

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

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, CONVCONTEXT, DdeConnect, DdeInitialize, HSZPAIR