PyTime C API

Added in version 3.13.

The clock C API provides access to system clocks. It is similar to the Python time module.

For C API related to the datetime module, see DateTime Objects.

Types

typePyTime_t

A timestamp or duration in nanoseconds, represented as a signed 64-bit integer.

The reference point for timestamps depends on the clock used. For example, PyTime_Time() returns timestamps relative to the UNIX epoch.

The supported range is around [-292.3 years; +292.3 years]. Using the Unix epoch (January 1st, 1970) as reference, the supported date range is around [1677-09-21; 2262-04-11]. The exact limits are exposed as constants:

PyTime_tPyTime_MIN

Minimum value of PyTime_t.

PyTime_tPyTime_MAX

Maximum value of PyTime_t.

Clock Functions

The following functions take a pointer to a PyTime_t that they set to the value of a particular clock. Details of each clock are given in the documentation of the corresponding Python function.

The functions return 0 on success, or -1 (with an exception set) on failure.

On integer overflow, they set the PyExc_OverflowError exception and set *result to the value clamped to the [PyTime_MIN;PyTime_MAX] range. (On current systems, integer overflows are likely caused by misconfigured system time.)

As any other C API (unless otherwise specified), the functions must be called with the GIL held.

intPyTime_Monotonic(PyTime_t*result)

Read the monotonic clock. See time.monotonic() for important details on this clock.

intPyTime_PerfCounter(PyTime_t*result)

Read the performance counter. See time.perf_counter() for important details on this clock.

intPyTime_Time(PyTime_t*result)

Read the “wall clock” time. See time.time() for details important on this clock.

Raw Clock Functions

Similar to clock functions, but don’t set an exception on error and don’t require the caller to hold the GIL.

On success, the functions return 0.

On failure, they set *result to 0 and return -1, without setting an exception. To get the cause of the error, acquire the GIL and call the regular (non-Raw) function. Note that the regular function may succeed after the Raw one failed.

intPyTime_MonotonicRaw(PyTime_t*result)

Similar to PyTime_Monotonic(), but don’t set an exception on error and don’t require holding the GIL.

intPyTime_PerfCounterRaw(PyTime_t*result)

Similar to PyTime_PerfCounter(), but don’t set an exception on error and don’t require holding the GIL.

intPyTime_TimeRaw(PyTime_t*result)

Similar to PyTime_Time(), but don’t set an exception on error and don’t require holding the GIL.

Conversion functions

doublePyTime_AsSecondsDouble(PyTime_tt)

Convert a timestamp to a number of seconds as a C double.

The function cannot fail, but note that double has limited accuracy for large values.