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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