Re: Avoid unecessary MemSet call (src/backend/utils/cache/relcache.c) - Mailing list pgsql-hackers

On Tue, May 17, 2022 at 07:52:30PM -0300, Ranier Vilela wrote:
> I found, I believe, a serious problem of incorrect usage of the memset api.
> Historically, people have relied on using memset or MemSet, using the
> variable name as an argument for the sizeof.
> While it works correctly, for arrays, when it comes to pointers to
> structures, things go awry.

Knowing how sizeof() works is required before using it - the same is true for
pointers.

> So throughout the code there are these misuses.

Why do you think it's a misuse ?

Take the first one as an example.  It says:

        GenericCosts costs;
        MemSet(&costs, 0, sizeof(costs));

You sent a patch to change it to sizeof(GenericCosts).

But it's not a pointer, so they are the same.

Is that true for every change in your patch ?

-- 
Justin