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How to call 16bitDLL from 32bitAPP?

davidotoole
davidotoole asked
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Last Modified: 2013-12-03

HellO!

Win95 includes a DLL, called DISPDIB.DLL. I need to call a function in
this DLL, twice: once at the beginning, and once at the end.
Unfortunately, it is not directly possible to call a 16bit function from
32bit code. I have had a 16bit program working that calls the proper
function in the DLL, so I know it works... but I need to write a 32bit
program of course.

I have read about thunking, and it will probably not be as hard because
I do not need to translate any pointers, as I am not passing any. Is
there any way to do this without assembly? It seems to me that
translating pointers and sizes would be a perfectly mechanical process,
and there should be a Thunk() function. Is there one? I think it would
be silly of MS not to have included something along those lines.

ALTERNATIVELY, is it possible to use DDE instead? Instead of
thunking I would like to set up a tiny 16-bit "server" that operates
this DLL, and allows my client (32bit app) to send it messages. Can this
be done through SendMessage? I don't need to pass/translate any
pointers, but I do need to return focus to the client.
Can I pass the client hWnd to the server, and have the server give focus
to the client? If I spawn the server from the client, how do I get its
hWnd in order to send a message to it?

thanks!
dto@iname.com
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Commented:
I think the easiest way is to use the WM_COPYDATA message, since the amount your data is quite small.

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