Re: warnings for invalid function casts

Hi,

On 2020-06-30 08:47:56 +0200, Peter Eisentraut wrote:
> Some time ago, there were some discussions about gcc warnings produced by
> -Wcast-function-type [0]. To clarify, while that thread seemed to imply
> that the warnings appear by default in some compiler version, this is not
> the case AFAICT, and the warnings are entirely optional.

Well, it's part of -Wextra. Which I think a fair number of people just
always enable...

> There are three subplots:
>
> 1. Changing the return type of load_external_function() and
> lookup_external_function() from PGFunction to a generic pointer type, which
> is what the discussion in [0] started out about.

To a generic *function pointer type*, right?

> 2. There is a bit of cheating in dynahash.c. They keycopy field is declared
> as a function pointer that returns a pointer to the destination, to match
> the signature of memcpy(), but then we assign strlcpy() to it, which returns
> size_t. Even though we never use the return value, I'm not sure whether
> this could break if size_t and pointers are of different sizes, which in
> turn is very unlikely.

I agree that it's a low risk,

> Is there anything we want to pursue further here?

You mean whether we want to do further changes in the vein of yours, or
whether we want to apply your patch?

Greetings,

Andres Freund