ba42248575
The C standard states:
> Unless explicitly stated otherwise, the functions described in this
> subclause order two wide characters the same way as two integers of
> the underlying integer type designated by wchar_t.
>
> [...]
>
> The wcscmp function returns an integer greater than, equal to, or
> less than zero, accordingly as the wide string pointed to by s1 is
> greater than, equal to, or less than the wide string pointed to by
> s2.
>
> [...]
>
> The wcsncmp function returns an integer greater than, equal to, or
> less than zero, accordingly as the possibly null-terminated array
> pointed to by s1 is greater than, equal to, or less than the
> possibly null-terminated array pointed to by s2.
- C Standard, 7.31.4.4. Wide string comparison functions
Cosmopolitan fails to obey this in cases where the difference between
two wide characters is larger than WCHAR_MAX.
This means that, for example, the following program:
#include <stdio.h>
#include <wchar.h>
#include <limits.h>
int main()
{
wchar_t str1[] = { WCHAR_MIN, L'\0' };
wchar_t str2[] = { WCHAR_MAX, L'\0' };
printf("%d\n", wcscmp(str1, str2));
printf("%d\n", wcsncmp(str1, str2, 2));
}
will print `1` twice, instead of the negative numbers mandated by the
standard (as WCHAR_MIN is less than WCHAR_MAX)
This patch fixes this, along with the associated Github issue,
https://github.com/jart/cosmopolitan/issues/783
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|---|---|---|
| .. | ||
| calls | ||
| crt | ||
| dns | ||
| elf | ||
| fmt | ||
| integral | ||
| intrin | ||
| isystem | ||
| linux | ||
| log | ||
| mem | ||
| nexgen32e | ||
| nt | ||
| runtime | ||
| sock | ||
| stdio | ||
| str | ||
| stubs | ||
| sysv | ||
| testlib | ||
| thread | ||
| time | ||
| tinymath | ||
| vga | ||
| x | ||
| zipos | ||
| ar.h | ||
| assert.h | ||
| atomic.h | ||
| complex.h | ||
| dce.h | ||
| disclaimer.inc | ||
| dos.h | ||
| errno.h | ||
| imag.internal.h | ||
| inttypes.h | ||
| iso646.internal.h | ||
| libc.mk | ||
| limits.h | ||
| literal.h | ||
| mach.h | ||
| macho.internal.h | ||
| macros.internal.h | ||
| math.h | ||
| notice.inc | ||
| notice.internal.h | ||
| paths.h | ||
| README.md | ||
| stdalign.internal.h | ||
| type2str.h | ||
| zip.h | ||
Cosmopolitan Standard Library
This directory defines static archives defining functions, like
printf(), mmap(), win32, etc. Please note that the Cosmopolitan
build configuration doesn't link any C/C++ library dependencies
by default, so you still have the flexibility to choose the one
provided by your system. If you'd prefer Cosmopolitan, just add
$(LIBC) and $(CRT) to your linker arguments.
Your library is compromised of many bite-sized static archives. We use the checkdeps tool to guarantee that the contents of the archives are organized in a logical way that's easy to use with or without our makefile infrastructure, since there's no cyclic dependencies.
The Cosmopolitan Library exports only the most stable canonical
system calls for all supported operating systems, regardless of
which platform is used for compilation. We polyfill many of the
APIs, e.g. read(), write() so they work consistently everywhere
while other apis, e.g. CreateWindowEx(), might only work on one
platform, in which case they become no-op functions on others.
Cosmopolitan polyfill wrappers will usually use the dollar sign naming convention, so they may be bypassed when necessary. This same convention is used when multiple implementations of string library and other performance-critical function are provided to allow Cosmopolitan to go fast on both old and newer computers.
We take an approach to configuration that relies heavily on the
compiler's dead code elimination pass (libc/dce.h). Most of the
code is written so that, for example, folks not wanting support
for OpenBSD can flip a bit in SUPPORT_VECTOR and that code will
be omitted from the build. The same is true for builds that are
tuned using -march=native which effectively asks the library to
not include runtime support hooks for x86 processors older than
what you use.
Please note that, unlike Cygwin or MinGW, Cosmopolitan does not achieve broad support by bolting on a POSIX emulation layer. We do nothing more than (in most cases) stateless API translations that get you 90% of the way there in a fast lightweight manner. We therefore can't address some of the subtle differences, such as the nuances of absolute paths on Windows. Our approach could be compared to something more along the lines of, "the Russians just used a pencil to write in space", versus spending millions researching a pen like NASA.