Describe the role of these APIs, key concepts that they depend on, and
expose the low-level API.
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
Provide data structures to capture a timestamp in two different
clocks, monitor the drift between those clocks, and using a base
instant with estimated drift convert between the clocks.
This provides the core technology to convert between system uptime and
an external continuous time scale like TAI (UTC without applying leap
seconds).
Signed-off-by: Peter A. Bigot <pab@pabigot.com>
sys/timeutil.h could not be used without including first
<zephyr/types.h> because s64_t type definition was missing.
Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>
The algorithm for converting broken-down civil time to seconds in the
POSIX epoch time scale would produce undefined behavior on a toolchain
that uses a 32-bit time_t in cases where the referenced time could not
be represented exactly.
However, there are use cases in Zephyr for civil time conversions
outside the 32-bit representable range of 1901-12-13T20:45:52Z through
2038-01-19T03:14:07Z inclusive.
Add new API that specifically returns a 64-bit signed seconds count, and
revise the existing API to detect out-of-range values and convert them
to a diagnosible error.
Closes#18465
Signed-off-by: Peter A. Bigot <pab@pabigot.com>
timeutil_timegm() does not modify the passed structure, so it should
indicate that in the signature (even though the GNU extension does not).
Signed-off-by: Peter A. Bigot <pab@pabigot.com>
Add a generic API to provide the inverse operation for gmtime and as a
home for future generic time-related functions that are not in POSIX.
Signed-off-by: Peter A. Bigot <pab@pabigot.com>
