I'm trying to call an external function in a DLL that has been provided to me. It was written in Delphi, but at least apparently declared to use C-style strings and the stdcall calling convention, so it should work.

But when I call it (whether or not I add ";Ansi" to the Alias section of the declaration) I get "Error calling external function %s at line ...".

That "%s" part of the message seems a bit unusual.

I did confirm that I get a different error message if the DLL isn't present. I also get a different error message (that fills in the function name instead of "%s") if I use an incorrect method name in the alias clause.

In case it's helpful, the declaration is like:

Function String Foo(String arg1, string arg2, String arg3) LIBRARY "libname.dll" alias for "FOO"

Yes, the name is capitalized in the DLL, when I look at it with "dumpbin /exports", though I doubt that matters. In case it's helpful, here's the relevant part of that output:

ordinal hint RVA name

1 0 0015C2E8 FOO

(I have changed the names for privacy of the 3rd party.)

Adding REF before the argument definitions also doesn't work, then I get an error about incorrect reference argument.

Any bright ideas? Thanks.