DdeGetLastError

3.1

#include <ddeml.h>

	UINT DdeGetLastError(idInst)
	DWORD idInst;	/* instance identifier, */

The DdeGetLastError function returns the most recent error value set by the failure of a Dynamic Data Exchange Management Library (DDEML) function and resets the error value to DMLERR_NO_ERROR.

Parameters

idInst

Specifies the application-instance identifier obtained by a previous call to the DdeInitialize function.

Return Value

The return value is the last error value. Following are the possible DDEML error values:

Value

Meaning

DMLERR_ADVACKTIMEOUT	A request for a synchronous advise transaction has timed out.
DMLERR_BUSY	The response to the transaction caused the DDE_FBUSY bit to be set.
DMLERR_DATAACKTIMEOUT	A request for a synchronous data transaction has timed out.
DMLERR_DLL_NOT_INITIALIZED	A DDEML function was called without first calling the DdeInitialize function, or an invalid instance identifier was passed to a DDEML function.
DMLERR_DLL_USAGE	An application initialized as APPCLASS_MONITOR has attempted to perform a DDE transaction, or an application initialized as APPCMD_CLIENTONLY has attempted to perform server transactions.
DMLERR_EXECACKTIMEOUT	A request for a synchronous execute transaction has timed out.
DMLERR_INVALIDPARAMETER	A parameter failed to be validated by the DDEML. Some of the possible causes are as follows:

The application used a data handle initialized with a different item-name handle than that required by the transaction.

The application used a data handle that was initialized with a different clipboard data format than that required by the transaction.

The application used a client-side conversation handle with a server-side function or vise versa.

The application used a freed data handle or string handle.

More than one instance of the application used the same object.

DMLERR_LOW_MEMORY	A DDEML application has created a prolonged race condition (where the server application outruns the client), causing large amounts of memory to be consumed.
DMLERR_MEMORY_ERROR	A memory allocation failed.
DMLERR_NO_CONV_ESTABLISHED	A client's attempt to establish a conversation has failed.
DMLERR_NOTPROCESSED	A transaction failed.
DMLERR_POKEACKTIMEOUT	A request for a synchronous poke transaction has timed out.
DMLERR_POSTMSG_FAILED	An internal call to the PostMessage function has failed.
Value	Meaning

DMLERR_REENTRANCY	An application instance with a synchronous transaction already in progress attempted to initiate another synchronous transaction, or the DdeEnableCallback function was called from within a DDEML callback function.
DMLERR_SERVER_DIED	A server-side transaction was attempted on a conversation that was terminated by the client, or the server terminated before completing a transaction.
DMLERR_SYS_ERROR	An internal error has occurred in the DDEML.
DMLERR_UNADVACKTIMEOUT	A request to end an advise transaction has timed out.
DMLERR_UNFOUND_QUEUE_ID	An invalid transaction identifier was passed to a DDEML function. Once the application has returned from an XTYP_XACT_COMPLETE callback, the transaction identifier for that callback is no longer valid.

Example

The following example calls the DdeGetLastError function if the DdeCreateDataHandle function fails:

DWORD idInst;
HDDEDATA hddeMyData;
HSZPAIR ahszp[2];
HSZ hszClock, hszTime;

/* Create string handles. */

hszClock = DdeCreateStringHandle(idInst, (LPSTR) "Clock",
    CP_WINANSI);
hszTime = DdeCreateStringHandle(idInst, (LPSTR) "Time",
    CP_WINANSI);

/* Copy handles to an HSZPAIR structure. */

ahszp[0].hszSvc   = hszClock;
ahszp[0].hszTopic = hszTime;
ahszp[1].hszSvc   = (HSZ) NULL;
ahszp[1].hszTopic = (HSZ) NULL;

/* Create a global memory object. */

hddeMyData = DdeCreateDataHandle(idInst, ahszp,
        sizeof(ahszp), 0, NULL, CF_TEXT, 0);
    if (hddeMyData == NULL)

        


        /*
         * Pass error value to application-defined error handling
         * function.
         */

        HandleError(DdeGetLastError(idInst));