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

[David Laight]

On Mon, 16 Feb 2026 21:11:18 +0100
Thomas Weißschuh <linux@xxxxxxxxxxxxxx> wrote:

> On 2026-02-06 19:11:17+0000, david.laight.linux@xxxxxxxxx wrote:
> > From: David Laight <david.laight.linux@xxxxxxxxx>
> > 
> > Add support for all the normal flag chacacters except '0' (zero pad).
> >   '-' left alignment.
> >   '+' and ' ' Sign characters for non-negative numbers.
> >   '#' adds 0x to hex numbers.
> > Partially support "%X", outputs lower case a..f the same as "%x".
> > 
> > Move the "%s" code in with the numeric formats to save a va_arg() call.
> > 
> > Prepend the sign (or "0x") after conversion to ascii and use the length
> > returned by u64toh_r() and u64toa_r().
> > Both needed for precision and zero-padding in the next patch.
> > 
> > Signed-off-by: David Laight <david.laight.linux@xxxxxxxxx>
> > ---
> > 
> > Changes for v2:
> > - Add support for left justifying fields (removed from patch 6).
> > - Merge in the changes from the old patch 8.
> > - Add support for "%#x" (formally part of patch 9).
> > 
> >  tools/include/nolibc/stdio.h | 97 ++++++++++++++++++++++++++----------
> >  1 file changed, 71 insertions(+), 26 deletions(-)  
> 
> (...)
> 
> > @@ -365,40 +384,62 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
> >  					goto do_output;
> >  				}
> >  
> > +				if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 's')) {
> > +					/* "%s" - character string. */
> > +					if (!v) {
> > +						outstr = "(null)";
> > +						len = 6;
> > +						goto do_output;
> > +					}
> > +					outstr = (void *)v;  
> 
> When building for i386:
> 
> In file included from ./nolibc.h:123,
>                  from ./ctype.h:8,
>                  from <command-line>:
> ./stdio.h: In function '__nolibc_printf':
> ./stdio.h:445:50: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>   445 |                                         outstr = (void *)v;
>       |
> 
> Needs a cast through (uintptr_t). Also instead of casting through
> (void *), please specify the actual target type that is expected.

Ok.

> 
> > +do_strnlen_output:
> > +					len = strnlen(outstr, INT_MAX);
> > +					goto do_output;
> > +				}  
> 
> (...)