fortify-headers/include/wchar.h, branch annotations

Remove wctomb

2025-11-10T22:55:25Z

It's unfortunately valid to pass a buffer smaller than MB_CUR_MAX to wctomb, so let's not trap on this. Moreover, it's supposed to be implemented in stdlib.h and not wchar.h anyway.

add initial clang support

2025-10-31T21:16:21Z

Co-Authored-By: jvoisin

avoid extension with clang

2025-10-31T21:16:21Z

It seems useless and triggers 'error: expected external declaration'

Make use of __builtin_dynamic_object_size

2025-10-31T21:16:21Z

GCC and Clang provide __builtin_dynamic_object_size (see documentation: https://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html), so we should make use of it when its available.

wctomb, wcrtomb: guard slow/trap path with MB_LEN_MAX

2019-03-07T00:05:34Z

This allows the compiler to optimize out the slow/trap path at all for the typical correct code: char buf[MB_LEN_MAX]; r = wctomb(buf, c); The change tries to keep the "unknown object size" case handling in wcrtomb() as is even if it seems redundant and not helping (we copy __buf to possibly undersized __s in any case) and inconsistent with wctomb() (where we let the original library method itself overwrite the possibly undersized __s).

Make use of builtins whenever possible

2019-02-25T13:17:08Z

Don't use extension in C++ code

2018-07-24T10:00:30Z

A few important notes: * __extension__ is a GNU C "alternate" keyword, not a C++ keyword.[1] * __extension__ is designed to work on "expressions"; it does work on #include_next in C mode, but it has no effect in C++ mode; the warning will still appear, if enabled, even with __extension__ preceding #include_next. This is because #include_next is not considered an expression in C++, so the compiler attaches __extension__ to the first expression of the header. All of this leads us to a build failure while building at least all Mozilla software. Moz has an alternate -isystem dir searched before /usr/include that overrides some headers, including . The first statement in each of these headers is a #pragma, and since __extension__ is looking for an expression, and #pragma is a "null" expression, we end up with the following error: dist/system_wrappers/features.h:1:9: error: '#pragma' is not allowed here Since __extension__ has no effect on #include_next in C++ mode anyway, and since it can cause breakage, this commit omits __extension__ in C++ mode. [1]: https://gcc.gnu.org/onlinedocs/gcc-6.4.0/gcc/Alternate-Keywords.html

Don't trap if an encoding error occurs in wcrtomb()

2017-08-22T10:38:36Z

The POSIX definition of wcrtomb (http://pubs.opengroup.org/onlinepubs/9699919799/functions/wcrtomb.html) states: "When wc is not a valid wide character, an encoding error shall occur. In this case, the function shall store the value of the macro [EILSEQ] in errno and shall return (size_t)-1; the conversion state shall be undefined." The fortify-headers implementation of wcrtomb interprets the result -1 as 18446744073709551615 bytes. Since this is the highest 64-bit number possible, it is pretty safe to say this will always be larger than any buffer provided to wcrtomb. Therefore, it traps. Fixes bug https://bugs.alpinelinux.org/issues/7681. Patch by A. Wilcox

Bump copyright year

2016-09-10T11:54:17Z

Fix wcrtomb() check

2015-07-15T14:55:56Z

This was breaking valid code, example: char c; wcrtomb(&c, L'0', st);

fortify-headers/include/wchar.h, branch annotations

Remove wctomb

add initial clang support

avoid __extension__ with clang

Make use of __builtin_dynamic_object_size

wctomb, wcrtomb: guard slow/trap path with MB_LEN_MAX

Make use of builtins whenever possible

Don't use __extension__ in C++ code

Don't trap if an encoding error occurs in wcrtomb()

Bump copyright year

Fix wcrtomb() check

avoid extension with clang

Don't use extension in C++ code