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>
don't require locking and can operate on user-specified timezones
as opposed to having to alter the environment to change a timezone.
This work was presented to the tzcode folks and it was generally
accepted, but there seems to be a lot of inertia.
builtin attributes for (for symmetry and consistency). In the future this
might change to use compiler-neutral macros. On the other hand I don't
know of any other compiler that provides other macros with similar
functionality, so why bother?
by the application, all NetBSD interfaces are made visible, even
if some other feature-test macro (like _POSIX_C_SOURCE) is defined.
<sys/featuretest.h> defined _NETBSD_SOURCE if none of _ANSI_SOURCE,
_POSIX_C_SOURCE and _XOPEN_SOURCE is defined, so as to preserve
existing behaviour.
This has two major advantages:
+ Programs that require non-POSIX facilities but define _POSIX_C_SOURCE
can trivially be overruled by putting -D_NETBSD_SOURCE in their CFLAGS.
+ It makes most of the #ifs simpler, in that they're all now ORs of the
various macros, rather than having checks for (!defined(_ANSI_SOURCE) ||
!defined(_POSIX_C_SOURCE) || !defined(_XOPEN_SOURCE)) all over the place.
I've tried not to change the semantics of the headers in any case where
_NETBSD_SOURCE wasn't defined, but there were some places where the
current semantics were clearly mad, and retaining them was harder than
correcting them. In particular, I've mostly normalised things so that
_ANSI_SOURCE gets you the smallest set of stuff, then _POSIX_C_SOURCE,
_XOPEN_SOURCE and _NETBSD_SOURCE in that order.
Tested by building for vax, encouraged by thorpej, and uncontested in
tech-userlevel for a week.
sysconf(_SC_CLK_TCK) return hz will work.
In detail:
__times13() returns values scaled by hz.
times() returns values scaled by 100.
<sys/times.h> renames times() to __times13().
_SC_CLK_TCK has changed from 3 to 39.
sysconf(3) returns 100.
sysconf(39) returns hz.
CLK_TCK is defined as sysconf(39).
as __null with egcs 1.0 (GCC 2.90) and above. As several headers are affected
by this change, move the definition into a new header file, <null.h>, to ease
maintenance.
offtime, timelocal, timegm, timeoff, gtime, time2posix, posix2time.
- Added prototypes for the currently stubbed out timer functions:
timer_{create,delete,getoverrun,gettime,settime}
When we get sysconf, we can define them in terms of the kernel's notion of
interrupts per second if we so choose. Until then, the constant value
seems to satisfy the requirements presented by ISO C and POSIX, even if it
may lie about the true number of clocks per second.
kamil