[cffi-devel] Re: calling a function of the same name from two DLLs

[Nikodemus Siivola]

"Jack Unrue" <jdunrue at gmail.com> writes:

> Hello, CFFI folks. What are the implications of declaring two foreign functions,
> each foreign name being the same but which are implemented in two separate
> DLLs? The specific case I have in mind is the Win32 function DllGetVersion,
> which can return different meta-data for comctl32.dll vs. shell32.dll.

>    (load-foreign-library "comctl32.dll")
>
>    (defcfun
>      ("DllGetVersion" comctl-dll-get-version)
>      HRESULT
>      (info :pointer))
>
>    (load-foreign-library "shell32.dll")
>
>    (defcfun
>      ("DllGetVersion" shell-dll-get-version)
>      HRESULT
>      (info :pointer))

For SBCL 1.0 at least both will be backed by the same foreign function,
namely the first one to be loaded.

The Right Thing, I believe, would be something like

 (load-foreign-library "foo.dll" :name :foo)

 (defcfun ("FooFun" foo-fun :library :foo) ...)

which would not be too hard to support on the SBCL end of things at least.

Cheers,

  -- Nikodemus              Schemer: "Buddha is small, clean, and serious."
                   Lispnik: "Buddha is big, has hairy armpits, and laughs."