From: Brian Inglis <Brian.Inglis@SystematicSw.ab.ca>
To: cygwin@cygwin.com
Subject: Re: should scanf be getting built supporting hexadecimal float
Date: Mon, 19 Apr 2021 09:17:48 -0600 [thread overview]
Message-ID: <91cf4bdd-9a97-6d6b-73af-01e891c22182@SystematicSw.ab.ca> (raw)
In-Reply-To: <189e0004-0cee-0e1d-2c2f-0acd7d8ca2fb@SystematicSw.ab.ca>
On 2021-04-19 09:07, Brian Inglis wrote:
> On 2021-04-18 22:09, Keith Thompson via Cygwin wrote:
>> The *scanf() functions don't handle hexadecimal floating-point input
>> (for example "0x1p+0" representing 1.0).
>> On Cygwin, the output (compiled with gcc or clang) is:
>> sscanf returned 1, x = 0 (expected 1), FAILED
>> On Ubuntu, the output is:
>> sscanf returned 1, x = 1, PASSED
>> Looking through the newlib sources (git://sourceware.org/git/newlib-cygwin.git),
>> this might be related to the _WANT_IO_C99_FORMATS macro, but I haven't
>> looked into
>> the details.
>> The test case passes on Cygwin when compiled with i686-w64-mingw32-gcc
>> or x86_64-w64-mingw32-gcc.
> This seems like an oversight as gdtoa-gethex.c was added about 2006 and scanf
> and strtod support it.
> See augmented STC with strtod added attached:
>
> $ gcc -o hexfloat-scanf-test{,.c}
> $ ./hexfloat-scanf-test
> sscanf returned 2, unscanned 'x1p+0', x = 0 (expected 1), FAILED
> strtod unscanned '', x = 1, PASSED
Should the Cygwin newlib build be enabling hex float support?
--
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada
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[Data in binary units and prefixes, physical quantities in SI.]
next prev parent reply other threads:[~2021-04-19 15:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-19 4:09 sscanf doesn't handle hexadecimal floating-point input Keith Thompson
2021-04-19 15:07 ` sscanf doesn't handle hexadecimal float but strtod does Brian Inglis
2021-04-19 15:17 ` Brian Inglis [this message]
2021-04-19 17:53 ` should scanf be getting built supporting hexadecimal float Corinna Vinschen
2021-04-19 20:12 ` Corinna Vinschen
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