🚀 go-pugleaf

In <1h0crpINNdvh@usenet.INS.CWRU.Edu> bu254@cleveland.Freenet.Edu (Stephen Groundwater) writes:


>In a previous article, bu254@cleveland.Freenet.Edu (Stephen Groundwater) says:
>[Stuff deleted]
>>This is the result of my dumping the hDrop memory that
>>comes on the WM_DROPFILES message, and my understanding of it.
>> 
>>The hDrop memory is a global memory object.
>>The drag-drop memory object consists of two parts, a header, and
>>a trailing bit.
>>The header is 8 bytes long in windows 3.1.
>>The trailer is however long it needs to be.
>> 
>>The header:
>> 
>>typedef struct tagDragHeader {
>>	UNIT wStructSize; /* Size of struct (8 bytes in this ver) */
>>	UINT x; /* x co-ord on window that is dropped on. (Client DC) */
>>	UINT y; /* y co-ord on window that is dropped on. (Client DC) */
>>	WORD wReserved; /* no known purpose, should be 0 */
>>	} DragHeader;
>> 
>>This is what I think the header structure is, the first three
>>fields I am more or less sure of, the fourth field is a mystery
>>to me, but in every drop I've seen it's been 0.
>> 

>Correction:
>I have now found out what the fourth field is, thanks to hints from
>blakeco@Microsoft.COM. The structure should be:

>typedef struct tagDRAGHEADER {
>  UINT wStructSize; // Same as before
>  UINT x; // Same as before
>  UINT y; // Same as before
>  BOOL fInClient; // True if drop is on client area,
>                  // false if anywhere else (title bar etc)
>  } DRAGHEADER;

>>The trailer:
>> 
>>The trailer is a series of null-terminated strings that contain
>>the strings that DragQueryFile() will return. The number of the
>>strings is not in any structure, so you don't need to worry about
>>that.

Actually, I believe the trailer is a null-terminated list of
null-terminated strings.  ie:

filename1\0filename2\0filename3\0\0

Without the last null DragQueryFile() won't know where the list ends
and will likely cause a protection error.


>>You should GlobalAlloc a block big enough for the header, and following
>>file names, and use the flag GMEM_DDESHARE when allocating.
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