Platform SDK: Interprocess Communications

DdeAddData

The DdeAddData function adds data to the specified dynamic data exchange (DDE) object. An application can add data starting at any offset from the beginning of the object. If new data overlaps data already in the object, the new data overwrites the old data in the bytes where the overlap occurs. The contents of locations in the object that have not been written to are undefined.

HDDEDATA DdeAddData(
  HDDEDATA hData,  // handle to DDE data object
  LPBYTE pSrc,     // pointer to source buffer
  DWORD cb,        // length of data
  DWORD cbOff      // offset within DDE data object
);

Parameters

hData: [in] Handle to the DDE object that receives additional data.
pSrc: [in] Pointer to a buffer containing the data to add to the DDE object.
cb: [in] Specifies the length, in bytes, of the data to be added to the DDE object, including the terminating NULL, if the data is a string.
cbOff: [in] Specifies an offset, in bytes, from the beginning of the DDE object. The additional data is copied to the object beginning at this offset.

Return Values

If the function succeeds, the return value is a new handle to the DDE object. The new handle is used in all references to the object.

If the function fails, the return value is zero.

Errors

The DdeGetLastError function can be used to get the error code, which can be one of the following values:

DMLERR_DLL_NOT_INITIALIZED
DMLERR_INVALIDPARAMETER
DMLERR_MEMORY_ERROR
DMLERR_NO_ERROR

Remarks

After a data handle has been used as a parameter in another Dynamic Data Exchange Management Library function or has been returned by a DDE callback function, the handle can be used only for read access to the DDE object identified by the handle.

If the amount of memory originally allocated is less than is needed to hold the added data, DdeAddData reallocates a global memory object of the appropriate size.

Requirements