invoking renamed foreign function

[Luís Oliveira]

You can look up both functions using foreign-symbol-pointer to decide which
one to call. You'd usually call the right one using
foreign-funcall-pointer, but perhaps you can defcfun both and call the
right one based on the lookup.

defcfun-ing non-existent functions will yield runtime warnings on some
implementations (notably SBCL) so perhaps you might want to implement both
the foreign-funcall-pointer and defcfun approaches and conditionalise them
accordingly.

HTH,
Luís

On Mon, May 29, 2017, 02:56 Anton Vodonosov <avodonosov at yandex.ru> wrote:

> Hello,
>
> OpenSSL renamed function SSLeay to OpenSSL_version_num.
> So, so depending on what version of library we work with we
> need to call either SSLeay or OpenSSL_version_num.
>
> What is the best way to do it?
>
> The following is one approach:
>
> (or (ignore-errors
>       (cffi:foreign-funcall "OpenSSL_version_num" :long))
>     (ignore-errors
>       (cffi:foreign-funcall "SSLeay" :long)))
>
>
> but it won't work on Corman Lisp because it doesn't
> support cffi:foreign-funcall.
>
> I would like to be fully portable. Is there a better way?
>
> Best regards,
> - Anton
>
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