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The worst issue I had with consts.sh for clock_gettime is how it defined too many clocks. So I looked into these clocks all day to figure out how how they overlap in functionality. I discovered counter-intuitive things such as how CLOCK_MONOTONIC should be CLOCK_UPTIME on MacOS and BSD, and that CLOCK_BOOTTIME should be CLOCK_MONOTONIC on MacOS / BSD. Windows 10 also has some incredible new APIs, that let us simplify clock_gettime(). - Linux CLOCK_REALTIME -> GetSystemTimePreciseAsFileTime() - Linux CLOCK_MONOTONIC -> QueryUnbiasedInterruptTimePrecise() - Linux CLOCK_MONOTONIC_RAW -> QueryUnbiasedInterruptTimePrecise() - Linux CLOCK_REALTIME_COARSE -> GetSystemTimeAsFileTime() - Linux CLOCK_MONOTONIC_COARSE -> QueryUnbiasedInterruptTime() - Linux CLOCK_BOOTTIME -> QueryInterruptTimePrecise() Documentation on the clock crew has been added to clock_gettime() in the docstring and in redbean's documentation too. You can read that to learn interesting facts about eight essential clocks that survived this purge. This is original research you will not find on Google, OpenAI, or Claude I've tested this change by porting *NSYNC to become fully clock agnostic since it has extensive tests for spotting irregularities in time. I have also included these tests in the default build so they no longer need to be run manually. Both CLOCK_REALTIME and CLOCK_MONOTONIC are good across the entire amd64 and arm64 test fleets.
39 lines
1.5 KiB
C
39 lines
1.5 KiB
C
#ifndef NSYNC_COUNTER_H_
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#define NSYNC_COUNTER_H_
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#include "third_party/nsync/atomic.h"
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#include "third_party/nsync/time.h"
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COSMOPOLITAN_C_START_
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/* An nsync_counter represents an unsigned integer that can count up and down,
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and wake waiters when zero. */
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typedef struct nsync_counter_s_ *nsync_counter;
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/* Return a freshly allocated nsync_counter with the specified value,
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of NULL if an nsync_counter cannot be created.
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Any non-NULL returned value should be passed to nsync_counter_free() when no
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longer needed. */
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nsync_counter nsync_counter_new(uint32_t value);
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/* Free resources associated with c. Requires that c was allocated by
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nsync_counter_new(), and no concurrent or future operations are applied to
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c. */
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void nsync_counter_free(nsync_counter c);
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/* Add delta to c, and return its new value. It is a checkable runtime error
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to decrement c below 0, or to increment c (i.e., apply a delta > 0) after a
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waiter has waited. */
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uint32_t nsync_counter_add(nsync_counter c, int32_t delta);
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/* Return the current value of c. */
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uint32_t nsync_counter_value(nsync_counter c);
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/* Wait until c has value 0, or until abs_deadline, then return
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the value of c. It is a checkable runtime error to increment c after
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a waiter may have been woken due to the counter reaching zero.
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If abs_deadline==nsync_time_no_deadline, the deadline
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is far in the future. */
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uint32_t nsync_counter_wait(nsync_counter c, int clock, nsync_time abs_deadline);
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COSMOPOLITAN_C_END_
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#endif /* NSYNC_COUNTER_H_ */
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