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Faraz Vahedi
d08296c7ab
Several standard library functions are specified to return an unqualified pointer while accepting a pointer to a potentially const-qualified object. N3020 addresses this behaviour, discarding qualifiers due to incompatible pointer types, by introducing qualifier-preserving macros for the affected set of standard library functions. Add `__qualsel()` helper to `<sys/cdefs.h>`, implemented using the generic selection, and define qualifier-preserving macros for that set of functions in `<string.h>`, `<wchar.h>`, and `<stdlib.h>`. Macros are gated on `_STDC_VERSION__ >= 202311L && !__cplusplus`, therefore there is no behavioural change for earlier C modes or C++ translation units. The kernel is likewise unaffected, as it does not include userland headers. As function-like macros, they are transparent except at a call site where the address-of operator is applied, the macro is suppressed via `#undef`, or the identifier appears in parenthesised form; all of which cause the underlying function designator to be used instead. Reviewed by: fuz Approved by: fuz (mentor) MFC after: 1 month Pull Request: https://github.com/freebsd/freebsd-src/pull/2288