Re: [PATCH v3] NULL.3const: Add documentation for NULL

[Jakub Wilk]

* Alejandro Colomar <alx.manpages@gmail.com>, 2022-07-24, 21:19:
> +.B "#define NULL  ((void *) 0)"
> +.fi
> +.SH DESCRIPTION
> +.B NULL
> +represents a null pointer constant.
> +.PP
> +According to POSIX,
> +it shall expand to an integer constant expression with the value
> +.B 0
> +cast to type
> +.IR "void *" .

Might be worth noting that the cast requirement was added only in 
POSIX.1-2008 aka SUSv4.

> +.SH CONFORMING TO
> +C99 and later;

It's in C89 too.

> +.I NULL \- NULL
> +is, surprisingly, undefined behavior, according to ISO C.

FWIW, I don't find it surprising at all.

--
Jakub Wilk