linux-kernel - Re: [PATCH v2 next 07/11] tools/nolibc/printf: Add support for conversion flags "#- +" and format "%X"

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Message-ID: <aYi0eqBb4GDa0Ina@1wt.eu>
Date: Sun, 8 Feb 2026 17:06:18 +0100
From: Willy Tarreau <w@....eu>
To: david.laight.linux@...il.com
Cc: Thomas Weißschuh <linux@...ssschuh.net>,
        linux-kernel@...r.kernel.org, Cheng Li <lechain@...il.com>
Subject: Re: [PATCH v2 next 07/11] tools/nolibc/printf: Add support for
 conversion flags "#- +" and format "%X"

Another point I didn't notice, which confused me while reading next
patch:

On Fri, Feb 06, 2026 at 07:11:17PM +0000, david.laight.linux@...il.com wrote:
> +			if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'c', 'd', 'i', 'u', 'x', 'p', 's')) {
>  				unsigned long long v;
>  				long long signed_v;
> -				char *out = tmpbuf;
> +				char *out = tmpbuf + 32;
> +				int sign = 0;
(...)
> +					if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'p', '#' - 1)) {
> +						/* "%p" and "%#x" need "0x" prepending. */
> +						sign = 'x' | '0' << 8;
(...)
> +				/* Add 0, 1 or 2 ("0x") sign characters left of any zero padding */
> +				for (; sign; sign >>= 8) {
> +					len++;
> +					*--out = sign;
> +				}

That's fine, but please mention in front of "sign" declaration something
like "/* may contain more than one char, starting with LSB */".

Willy