[cmake-developers] ExternalProject can't have interface library as a dependency

[Stephen Kelly]

Andrey Pokrovskiy wrote:

> [Moved from cmake users mailing list]
> 
> I have the following construction:
> 
> ExternalProject_Add(
>         websockets_ep
>         DEPENDS ev openssl
>         ...)
> 
> But it so happened, that "openssl" is an INTERFACE library. It is an
> INTERFACE library, because I created it with add_library(openssl
> INTEFACE) and then populated corresponding INCLUDE and LINK
> properties. 

Sorry, I forgot to follow up on this on the user list.

You probably want an IMPORT library instead of an INTERFACE one. That might 
already work for your dependency case with existing cmake releases.

Thanks,

Steve.