The wcsnlen(3) function conforms to POSIX.1-2008 and is an addition to the
ISO C standard.
size_t wcsnlen(const wchar_t *s, size_t maxlen);
The wcsnlen(3) function computes the number of wide-characters in a wide-
-string to which s points, not including NULL terminating wide-character
code and checking no more than maxlen wide-characters. This function never
examines wide-characters beyond a wide-string of maxlen size.
This function is a safer version of wcslen(3):
size_t wcslen(const wchar_t *s);
Update STANDARDS section of wmemchr(3) describing wide-character functions.
These changes conforms to the C11 standard
References:
- 7.27.1/3 Components of time (struct timespec)
- 7.27.2.5 The timespec_get function
According to ISO/IEC 9899:201x (draft) <time.h> defines the timespec
structure and declares the timespec_get(3) function with TIME_UTC
definition.
According to a C++17 standard draft <ctime> offers the same interface in
the std:: namespace.
The timespec_get function modifies the timespec object pointed by ts
to hold the current calendar time in the given base. The standard notes
only the TIME_UTC base with implementation defined value, set it to 1
as zero is reserved for error handling. Once operation was successful this
function returns passed base, otherwise exits with zero.
The timespec struct was already part of the POSIX standard in <time.h>.
Enable this interface unconditionally in the header to allow to use it
in a code prior C11 and C++17 as an extension.
Review notes from <christos>
This declaration conforms to the C11 standard
Reference: ISO/IEC 9899:201x 7.2 Diagnostics <assert.h>
_Static_assert performs compile-time assertion checking.
According to ISO/IEC 9899:201x (draft) 7.2 Diagnostics <assert.h> defines
the static_assert macro which expands to _Static_assert. It's not
conditionalized by NDEBUG like the assert macro.
According to ISO/IEC N3242=11-0012 (C++1x) the <cassert> header shall
define only the assert macro, but not static_assert as it's already part
of the C++11 language.
Allow to define static_assert in C++ prior the C++11 standard. It might be
broken but a nonstandard C++ compiler might support C11-like _Static_assert
feature. Note that it's fatal for g++ 5.4, but it works for clang++ 3.8.1.
Approved by <joerg>.
This header conforms to the C11 standard
Reference: ISO/IEC 9899:201x 7.15 Alignment <stdalign.h>
According to ISO/IEC 9899:201x (draft) 7.15 Alignment <stdalign.h> defines
four macros:
- alignas which expands to _Alignas
- alignof which expands to _Alignof
- __alignas_is_defined and __alignof_is_defined which both expand to 1
The _Alignas declaration appears as one of the type specifiers to modify
the alignment requirement of the object being declared.
The _Alignof operator is used to query the alignment requirement of its
operand type.
ISO/IEC N3242=11-0012 (C++1x) and ISO/IEC N3797 (C++1y) both note a header
<cstdalign> which defines only __alignas_is_defined and shall not define
the alignas macro. It misses the alignof case as it's probably based on an
older C1x draft, which defined only alignas. Assume that this is a bug in
the standard and treat alignof the same way as alignas in C++11.
Allow to define alignas and alignof in C++ prior the C++11 standard. It
might be broken but a nonstandard C++ compiler might support C11-like
_Alignas and _Alignof. Note that it's fatal for g++(1) v.5.4.
This header conforms to the C11 standard
Reference: ISO/IEC 9899:201x 7.23 _Noreturn <stdnoreturn.h>
According to ISO/IEC 9899:201x (draft) <stdnoreturn.> defines the
noreturn macro which expands to _Noreturn.
The _Noreturn keyword appears in a function declaration and specifies
that the function does not return by reaching the end of the function
body.
Design choices:
- don't implicitly break C++ code including this header with #error
C++11 offers [[noreturn]] which conflicts with C11 _Noreturn
- don't check for __STDC_VERSION__, everybody is free to reuse it with
a nonstandard compiler not conforming to C11 but supporting _Noreturn
gcc(1) and clang(1) support _Noreturn in -std=c99 and older standards
this follows <stdbool.h> choice for not checking for C99
- follow <stdbool.h> and declare the __noreturn_is_defined guard
- use a standard header guard (_STDNORETURN_H_), similar to <stdbool.h>
Reviewed by <pgoyette> and <joerg>
Adding a whole extra header file just for this is not the optimal
solution... but stuffing it in with anything else exposes things that
otherwise wouldn't be.
Nothing in userland should use <sys/semaphore.h> directly, and if some
foolish third-party software should decide to do so anyway in spite of
the instructions to the contrary I will ruthlessly break it later when
the big kernel includes cleanup finally happens.
Reported by Kamil Rytarowski, and, as it turns out, also by Klaus
Heinz in 2008.
rather than doing the machine/ansi.h #ifdef dance, as it doesn't matter
much what symbols utmp.h exposes. This could be tightened later when we
manage to do enough include cleanup to make such dances less expensive
to maintain.
Also, dumprestore.h needs ufs/ufs/dinode.h; in talkd.h use unsigned
char instead of u_char; and in timed.h include limits.h and use
_POSIX_HOST_NAME_MAX instead of MAXHOSTNAMELEN as the latter would
require sys/param.h.
