Timestamp functions relating to points in time (including the current time)
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const absolute_time_t | at_the_end_of_time |
| | The timestamp representing the end of time; this is actually not the maximum possible timestamp, but is set to 0x7fffffff_ffffffff microseconds to avoid sign overflows with time arithmetic. This is almost 300,000 years, so should be sufficient.
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const absolute_time_t | nil_time |
| | The timestamp representing a null timestamp.
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Timestamp functions relating to points in time (including the current time)
These are functions for dealing with timestamps (i.e. instants in time) represented by the type absolute_time_t. This opaque type is provided to help prevent accidental mixing of timestamps and relative time values.
◆ absolute_time_diff_us()
Return the difference in microseconds between two timestamps.
- Note
- be careful when diffing against large timestamps (e.g. at_the_end_of_time) as the signed integer may overflow.
- Parameters
-
| from | the first timestamp |
| to | the second timestamp |
- Returns
- the number of microseconds between the two timestamps (positive if
to is after from except in case of overflow)
◆ absolute_time_min()
Return the earlier of two timestamps.
- Parameters
-
| a | the first timestamp |
| b | the second timestamp |
- Returns
- the earlier of the two timestamps
◆ delayed_by_ms()
Return a timestamp value obtained by adding a number of milliseconds to another timestamp.
- Parameters
-
| t | the base timestamp |
| ms | the number of milliseconds to add |
- Returns
- the timestamp representing the resulting time
◆ delayed_by_us()
Return a timestamp value obtained by adding a number of microseconds to another timestamp.
- Parameters
-
| t | the base timestamp |
| us | the number of microseconds to add |
- Returns
- the timestamp representing the resulting time
◆ from_us_since_boot()
convert a number of microseconds since boot to an absolute_time_t
fn from_us_since_boot
- Parameters
-
| us_since_boot | number of microseconds since boot |
- Returns
- an absolute time equivalent to us_since_boot
◆ get_absolute_time()
Return a representation of the current time.
Returns an opaque high fidelity representation of the current time sampled during the call.
- Returns
- the absolute time (now) of the hardware timer
- See also
- absolute_time_t
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sleep_until()
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time_us_64()
◆ is_at_the_end_of_time()
Determine if the given timestamp is "at_the_end_of_time".
- Parameters
-
- Returns
- true if the timestamp is at_the_end_of_time
- See also
- at_the_end_of_time
◆ is_nil_time()
Determine if the given timestamp is nil.
- Parameters
-
- Returns
- true if the timestamp is nil
- See also
- nil_time
◆ make_timeout_time_ms()
Convenience method to get the timestamp a number of milliseconds from the current time.
- Parameters
-
| ms | the number of milliseconds to add to the current timestamp |
- Returns
- the future timestamp
◆ make_timeout_time_us()
Convenience method to get the timestamp a number of microseconds from the current time.
- Parameters
-
| us | the number of microseconds to add to the current timestamp |
- Returns
- the future timestamp
◆ to_ms_since_boot()
Convert a timestamp into a number of milliseconds since boot.
fn to_ms_since_boot
- Parameters
-
- Returns
- the number of milliseconds since boot represented by t
- See also
- to_us_since_boot()
◆ to_us_since_boot()
convert an absolute_time_t into a number of microseconds since boot.
fn to_us_since_boot
- Parameters
-
| t | the absolute time to convert |
- Returns
- a number of microseconds since boot, equivalent to t
◆ update_us_since_boot()
| static void update_us_since_boot |
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absolute_time_t * |
t, |
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uint64_t |
us_since_boot |
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inlinestatic |
update an absolute_time_t value to represent a given number of microseconds since boot
fn update_us_since_boot
- Parameters
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| t | the absolute time value to update |
| us_since_boot | the number of microseconds since boot to represent. Note this should be representable as a signed 64 bit integer |
v1.5.0