On Tuesday 18 November 2025 16:46:43 Pali Rohár wrote:
> On Monday 17 November 2025 22:06:40 Martin Storsjö wrote:
> > On Mon, 17 Nov 2025, Pali Rohár wrote:
> > 
> > > On Monday 17 November 2025 17:13:56 Martin Storsjö wrote:
> > > > On Sat, 25 Oct 2025, Pali Rohár wrote:
> > > > 
> > > > > Format %Z takes pointer to ANSI_STRING or UNICODE_STRING based on the
> > > > > wideness of format.
> > > > > 
> > > > > In this mingw-w64 implementation (same as in UCRT) the uppercase 
> > > > > format %Z
> > > > > has the same default wideness as uppercase format %S when no h, l or w
> > > > > modifier is specified.
> > > > > 
> > > > > Format %Z is supported by crtdll, msvcrt and UCRT libraries. There 
> > > > > are some
> > > > > differences between individual CRT versions regarding the wide 
> > > > > wprintf(%lZ),
> > > > > narrow printf(%Z/%lZ) and whether nul chars in ANSI_STRING are 
> > > > > accepted by
> > > > > wprintf or not. In mingw-w64 for compatibility reasons are accepted.
> > > > 
> > > > The last sentence, "In mingw-w64 for compatibility reasons are 
> > > > accepted."
> > > > seems like it is missing something, in order to make sense.
> > > 
> > > Ah, right, there is missing "they" (nul chars). Should be "they are 
> > > accepted".
> > > 
> > > > > diff --git a/mingw-w64-crt/stdio/mingw_pformat.c 
> > > > > b/mingw-w64-crt/stdio/mingw_pformat.c
> > > > > index bdc7eba2a573..ded916c9a2bc 100644
> > > > > --- a/mingw-w64-crt/stdio/mingw_pformat.c
> > > > > +++ b/mingw-w64-crt/stdio/mingw_pformat.c
> > > > > @@ -66,6 +66,7 @@
> > > > > #include <limits.h>
> > > > > #include <locale.h>
> > > > > #include <wchar.h>
> > > > > +#include <ntdef.h>
> > > > > 
> > > > > #ifdef __ENABLE_DFP
> > > > > #ifndef __STDC_WANT_DEC_FP__
> > > > > @@ -2558,6 +2559,64 @@ __pformat (int flags, void *dest, int max, 
> > > > > const APICHAR *fmt, va_list argv)
> > > > >                */
> > > > >               __pformat_puts( va_arg( argv, char * ), &stream );
> > > > >             goto format_scan;
> > > > > +
> > > > > +          case 'Z':
> > > > > +            /*
> > > > > +             * The logic for `%Z` length modifier is quite 
> > > > > complicated.
> > > > > +             *
> > > > > +             * for printf:
> > > > > +             * `%Z`  - UNICODE_STRING for UCRT; ANSI_STRING for 
> > > > > crtdll,msvcrt10,msvcrt,msvcr80-msvcr120
> > > > > +             * `%hZ` - ANSI_STRING
> > > > > +             * `%lZ` - UNICODE_STRING for UCRT; ANSI_STRING for 
> > > > > crtdll,msvcrt10,msvcrt,msvcr80-msvcr120
> > > > > +             * `%wZ` - UNICODE_STRING
> > > > > +             *
> > > > > +             * for wprintf:
> > > > > +             * `%Z`  - ANSI_STRING
> > > > > +             * `%hZ` - ANSI_STRING
> > > > > +             * `%lZ` - UNICODE_STRING for UCRT; ANSI_STRING for 
> > > > > crtdll,msvcrt10,msvcrt,msvcr80-msvcr120
> > > > > +             * `%wZ` - UNICODE_STRING
> > > > > +             *
> > > > > +             * There are some other changes between versions 
> > > > > regarding nul chars.
> > > > > +             * - msvcrt since Vista, msvcr80+ and UCRT do not accept 
> > > > > nul chars in ANSI_STRING for wprintf. They stop at nul char and 
> > > > > returns -1.
> > > > > +             * - crtdll, msvcrt10 and msvcrt before Vista accept nul 
> > > > > char in ANSI_STRING for wprintf, but ANSI_STRING content after nul 
> > > > > char is discarded.
> > > > 
> > > > This explanation doesn't feel like it makes sense to me. If it accepts 
> > > > the
> > > > nul char, the wouldn't it also proceed after that? So do you say that it
> > > > includes the single nul char in the output, but nothing after it? While 
> > > > the
> > > > logical thing would be to either stop at the nul (not outputting it) or
> > > > include everything?
> > > 
> > > I used term "accept" whether wprintf will continue or immediately
> > > returns -1. I think that this was the main confusing here.
> > 
> > No, the main confusion here is that some of the sentences here are
> > contradicting themselves. The core of the confusion is above:
> > 
> > "crtdll, msvcrt10 and msvcrt before Vista accept nul char in ANSI_STRING for
> > wprintf, but ANSI_STRING content after nul char is discarded."
> > 
> > Here you describe two different behaviours for ANSI_STRING. Do you mean one
> > behaviour for ANSI_STRING and one for UNICODE_STRING?
> > 
> > // Martin
> 
> Ok, I will to rephrase that sentence:
> 
> crtdll, msvcrt10 and msvcrt before Vista accept ANSI_STRING with nul
> chars in wprintf call, but the first nul char and everything after it in
> the ANSI_STRING content is ignored and not printed by wprintf at all.

It is more clear my above last comment about behavior?


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