[swift-evolution] Opaque Pointers in Swift

[Cory Benfield]

> On 24 Oct 2017, at 18:11, Félix Cloutier <felixcloutier at icloud.com> wrote:
> 
> Could you do a conditional typealias?

I don’t *think* so. In the case of OpenSSL the #define you want to use is OPENSSL_VERSION_NUMBER, which is defined in an OpenSSL header file. As far as I know, the Swift compiler does not see #defines from C header files when compiling Swift code (some experimenting suggests that this is still true, though I am not *certain* of that).

That would mean we’d have to pass this as a build flag with -D, which doesn’t really work with distribution via SwiftPM, and also would require that users know that this flag needs to be passed for newer OpenSSLs.

Cory