On 2016-10-17 16:16:37 -0400, Robert Haas wrote:
> I wouldn't think that cross-file references would be especially
> common. Functions that take PG_FUNCTION_ARGS and return Datum aren't
> a lot of fun to call from C. But maybe I'm wrong.
There's a fair number of DirectFunctionCall$Ns over the backend.
Greetings,
Andres Freund