The *scanf() functions don't handle hexadecimal floating-point input
(for example "0x1p+0" representing 1.0).
A test program:
#include <stdio.h>
int main(void) {
int ok = 1;
float x = -1.0;
int result = sscanf("0x1p+0", "%f", &x);
const float expected_x = 1.0;
const int expected_result = 1;
printf("sscanf returned %d", result);
if (result != expected_result) {
ok = 0;
printf(" (expected %d)", expected_result);
}
printf(", x = %g", x);
if (x != expected_x) {
ok = 0;
printf(" (expected %g)", expected_x);
}
puts(ok ? ", PASSED" : ", FAILED");
}
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.
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