BUG: realloc(p,0) should be consistent with malloc(0)

[Alejandro Colomar]

Hi Paul,

On Thu, Jun 19, 2025 at 08:07:35PM +0000, Wilco Dijkstra wrote:
> Hi Paul,
> 
> > 2. When p is not null, realloc(p,0) frees p, returns NULL, and sets
> > errno=EINVAL. This conforms to both POSIX.1-2017 and POSIX.1-2024.
> 
> That's interesting, was POSIX getting the idea of setting errno from AIX perhaps?
> 
> However POSIX.1-2024 actually requires that the old block must not be freed
> if errno is set...

Indeed, I have a hard time reading POSIX.1-2024 as allowing realloc(3)
to free the pointer on EINVAL.  I don't find it clear, but I'd say it
doesn't allow it because it doesn't say it can do it.

At the very least, it's a very contorted reading of the standard.


Have a lovely day!
Alex

> 
> Cheers,
> Wilco 

-- 
<https://www.alejandro-colomar.es/>
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