timemodule.c

/* Time module */

#include "Python.h"
#include "pycore_fileutils.h"     // _Py_BEGIN_SUPPRESS_IPH
#include "pycore_moduleobject.h"  // _PyModule_GetState()
#include "pycore_namespace.h"     // _PyNamespace_New()
#include "pycore_runtime.h"       // _Py_ID()
#include "pycore_time.h"          // _PyTimeFraction

#include <time.h>                 // clock()
#ifdef HAVE_SYS_TIMES_H
#  include <sys/times.h>          // times()
#endif
#ifdef HAVE_SYS_TYPES_H
#  include <sys/types.h>
#endif
#if defined(HAVE_SYS_RESOURCE_H)
#  include <sys/resource.h>       // getrusage(RUSAGE_SELF)
#endif
#ifdef QUICKWIN
# include <io.h>
#endif
#if defined(HAVE_PTHREAD_H)
#  include <pthread.h>            // pthread_getcpuclockid()
#endif
#if defined(_AIX)
#   include <sys/thread.h>
#endif
#if defined(__WATCOMC__) && !defined(__QNX__)
#  include <i86.h>
#else
#  ifdef MS_WINDOWS
#    ifndef WIN32_LEAN_AND_MEAN
#      define WIN32_LEAN_AND_MEAN
#    endif
#    include <windows.h>
#  endif /* MS_WINDOWS */
#endif /* !__WATCOMC__ || __QNX__ */

#ifdef _Py_MEMORY_SANITIZER
#  include <sanitizer/msan_interface.h>
#endif

#ifdef _MSC_VER
#  define _Py_timezone _timezone
#  define _Py_daylight _daylight
#  define _Py_tzname _tzname
#else
#  define _Py_timezone timezone
#  define _Py_daylight daylight
#  define _Py_tzname tzname
#endif

#if defined(__APPLE__ ) && defined(__has_builtin)
#  if __has_builtin(__builtin_available)
#    define HAVE_CLOCK_GETTIME_RUNTIME __builtin_available(macOS 10.12, iOS 10.0, tvOS 10.0, watchOS 3.0, *)
#  endif
#endif
#ifndef HAVE_CLOCK_GETTIME_RUNTIME
#  define HAVE_CLOCK_GETTIME_RUNTIME 1
#endif


#define SEC_TO_NS (1000 * 1000 * 1000)


/*[clinic input]
module time
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=a668a08771581f36]*/


/* Forward declarations */
static int pysleep(PyTime_t timeout);


typedef struct {
    PyTypeObject *struct_time_type;
// gh-115714: Don't use times() on WASI.
#if defined(HAVE_TIMES) && !defined(__wasi__)
    // times() clock frequency in hertz
    _PyTimeFraction times_base;
#endif
#ifdef HAVE_CLOCK
    // clock() frequency in hertz
    _PyTimeFraction clock_base;
#endif
} time_module_state;

static inline time_module_state*
get_time_state(PyObject *module)
{
    void *state = _PyModule_GetState(module);
    assert(state != NULL);
    return (time_module_state *)state;
}


static PyObject*
_PyFloat_FromPyTime(PyTime_t t)
{
    double d = PyTime_AsSecondsDouble(t);
    return PyFloat_FromDouble(d);
}


static PyObject *
time_time(PyObject *self, PyObject *unused)
{
    PyTime_t t;
    if (PyTime_Time(&t) < 0) {
        return NULL;
    }
    return _PyFloat_FromPyTime(t);
}


PyDoc_STRVAR(time_doc,
"time() -> floating-point number\n\
\n\
Return the current time in seconds since the Epoch.\n\
Fractions of a second may be present if the system clock provides them.");

static PyObject *
time_time_ns(PyObject *self, PyObject *unused)
{
    PyTime_t t;
    if (PyTime_Time(&t) < 0) {
        return NULL;
    }
    return _PyTime_AsLong(t);
}

PyDoc_STRVAR(time_ns_doc,
"time_ns() -> int\n\
\n\
Return the current time in nanoseconds since the Epoch.");

#ifdef HAVE_CLOCK

#ifndef CLOCKS_PER_SEC
#  ifdef CLK_TCK
#    define CLOCKS_PER_SEC CLK_TCK
#  else
#    define CLOCKS_PER_SEC 1000000
#  endif
#endif

static int
py_clock(time_module_state *state, PyTime_t *tp, _Py_clock_info_t *info)
{
    _PyTimeFraction *base = &state->clock_base;

    if (info) {
        info->implementation = "clock()";
        info->resolution = _PyTimeFraction_Resolution(base);
        info->monotonic = 1;
        info->adjustable = 0;
    }

    clock_t ticks = clock();
    if (ticks == (clock_t)-1) {
        PyErr_SetString(PyExc_RuntimeError,
                        "the processor time used is not available "
                        "or its value cannot be represented");
        return -1;
    }
    *tp = _PyTimeFraction_Mul(ticks, base);
    return 0;
}
#endif /* HAVE_CLOCK */


#ifdef HAVE_CLOCK_GETTIME

#ifdef __APPLE__
/*
 * The clock_* functions will be removed from the module
 * dict entirely when the C API is not available.
 */
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunguarded-availability"
#endif

static int
time_clockid_converter(PyObject *obj, clockid_t *p)
{
#ifdef _AIX
    long long clk_id = PyLong_AsLongLong(obj);
#else
    int clk_id = PyLong_AsInt(obj);
#endif
    if (clk_id == -1 && PyErr_Occurred()) {
        PyErr_Format(PyExc_TypeError,
                     "clk_id should be integer, not %s",
                     _PyType_Name(Py_TYPE(obj)));
        return 0;
    }

    // Make sure that we picked the right type (check sizes type)
    Py_BUILD_ASSERT(sizeof(clk_id) == sizeof(*p));
    *p = (clockid_t)clk_id;
    return 1;
}

/*[python input]

class clockid_t_converter(CConverter):
    type = "clockid_t"
    converter = 'time_clockid_converter'

[python start generated code]*/
/*[python end generated code: output=da39a3ee5e6b4b0d input=53867111501f46c8]*/


/*[clinic input]
time.clock_gettime

    clk_id: clockid_t
    /

Return the time of the specified clock clk_id as a float.
[clinic start generated code]*/

static PyObject *
time_clock_gettime_impl(PyObject *module, clockid_t clk_id)
/*[clinic end generated code: output=832b9ebc03328020 input=7e89fcc42ca15e5d]*/
{
    struct timespec tp;
    int ret = clock_gettime(clk_id, &tp);
    if (ret != 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return NULL;
    }
    return PyFloat_FromDouble(tp.tv_sec + tp.tv_nsec * 1e-9);
}

/*[clinic input]
time.clock_gettime_ns

    clk_id: clockid_t
    /

Return the time of the specified clock clk_id as nanoseconds (int).
[clinic start generated code]*/

static PyObject *
time_clock_gettime_ns_impl(PyObject *module, clockid_t clk_id)
/*[clinic end generated code: output=4a045c3a36e60044 input=aabc248db8c8e3e5]*/
{
    struct timespec ts;
    int ret = clock_gettime(clk_id, &ts);
    if (ret != 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return NULL;
    }

    PyTime_t t;
    if (_PyTime_FromTimespec(&t, &ts) < 0) {
        return NULL;
    }
    return _PyTime_AsLong(t);
}
#endif   /* HAVE_CLOCK_GETTIME */

#ifdef HAVE_CLOCK_SETTIME
static PyObject *
time_clock_settime(PyObject *self, PyObject *args)
{
    int clk_id;
    PyObject *obj;
    PyTime_t t;
    struct timespec tp;
    int ret;

    if (!PyArg_ParseTuple(args, "iO:clock_settime", &clk_id, &obj))
        return NULL;

    if (_PyTime_FromSecondsObject(&t, obj, _PyTime_ROUND_FLOOR) < 0)
        return NULL;

    if (_PyTime_AsTimespec(t, &tp) == -1)
        return NULL;

    ret = clock_settime((clockid_t)clk_id, &tp);
    if (ret != 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return NULL;
    }
    Py_RETURN_NONE;
}

PyDoc_STRVAR(clock_settime_doc,
"clock_settime(clk_id, time)\n\
\n\
Set the time of the specified clock clk_id.");

static PyObject *
time_clock_settime_ns(PyObject *self, PyObject *args)
{
    int clk_id;
    PyObject *obj;
    PyTime_t t;
    struct timespec ts;
    int ret;

    if (!PyArg_ParseTuple(args, "iO:clock_settime", &clk_id, &obj)) {
        return NULL;
    }

    if (_PyTime_FromLong(&t, obj) < 0) {
        return NULL;
    }
    if (_PyTime_AsTimespec(t, &ts) == -1) {
        return NULL;
    }

    ret = clock_settime((clockid_t)clk_id, &ts);
    if (ret != 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return NULL;
    }
    Py_RETURN_NONE;
}

PyDoc_STRVAR(clock_settime_ns_doc,
"clock_settime_ns(clk_id, time)\n\
\n\
Set the time of the specified clock clk_id with nanoseconds.");
#endif   /* HAVE_CLOCK_SETTIME */

#ifdef HAVE_CLOCK_GETRES
static PyObject *
time_clock_getres(PyObject *self, PyObject *args)
{
    int ret;
    int clk_id;
    struct timespec tp;

    if (!PyArg_ParseTuple(args, "i:clock_getres", &clk_id))
        return NULL;

    ret = clock_getres((clockid_t)clk_id, &tp);
    if (ret != 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return NULL;
    }

    return PyFloat_FromDouble(tp.tv_sec + tp.tv_nsec * 1e-9);
}

PyDoc_STRVAR(clock_getres_doc,
"clock_getres(clk_id) -> floating-point number\n\
\n\
Return the resolution (precision) of the specified clock clk_id.");

#ifdef __APPLE__
#pragma clang diagnostic pop
#endif

#endif   /* HAVE_CLOCK_GETRES */

#ifdef HAVE_PTHREAD_GETCPUCLOCKID
static PyObject *
time_pthread_getcpuclockid(PyObject *self, PyObject *args)
{
    unsigned long thread_id;
    int err;
    clockid_t clk_id;
    if (!PyArg_ParseTuple(args, "k:pthread_getcpuclockid", &thread_id)) {
        return NULL;
    }
    err = pthread_getcpuclockid((pthread_t)thread_id, &clk_id);
    if (err) {
        errno = err;
        PyErr_SetFromErrno(PyExc_OSError);
        return NULL;
    }
#ifdef _Py_MEMORY_SANITIZER
    __msan_unpoison(&clk_id, sizeof(clk_id));
#endif
    return PyLong_FromLong(clk_id);
}

PyDoc_STRVAR(pthread_getcpuclockid_doc,
"pthread_getcpuclockid(thread_id) -> int\n\
\n\
Return the clk_id of a thread's CPU time clock.");
#endif /* HAVE_PTHREAD_GETCPUCLOCKID */

static PyObject *
time_sleep(PyObject *self, PyObject *timeout_obj)
{
    if (PySys_Audit("time.sleep", "O", timeout_obj) < 0) {
        return NULL;
    }

    PyTime_t timeout;
    if (_PyTime_FromSecondsObject(&timeout, timeout_obj, _PyTime_ROUND_TIMEOUT))
        return NULL;
    if (timeout < 0) {
        PyErr_SetString(PyExc_ValueError,
                        "sleep length must be non-negative");
        return NULL;
    }
    if (pysleep(timeout) != 0) {
        return NULL;
    }
    Py_RETURN_NONE;
}

PyDoc_STRVAR(sleep_doc,
"sleep(seconds)\n\
\n\
Delay execution for a given number of seconds.  The argument may be\n\
a floating-point number for subsecond precision.");

static PyStructSequence_Field struct_time_type_fields[] = {
    {"tm_year", "year, for example, 1993"},
    {"tm_mon", "month of year, range [1, 12]"},
    {"tm_mday", "day of month, range [1, 31]"},
    {"tm_hour", "hours, range [0, 23]"},
    {"tm_min", "minutes, range [0, 59]"},
    {"tm_sec", "seconds, range [0, 61])"},
    {"tm_wday", "day of week, range [0, 6], Monday is 0"},
    {"tm_yday", "day of year, range [1, 366]"},
    {"tm_isdst", "1 if summer time is in effect, 0 if not, and -1 if unknown"},
    {"tm_zone", "abbreviation of timezone name"},
    {"tm_gmtoff", "offset from UTC in seconds"},
    {0}
};

static PyStructSequence_Desc struct_time_type_desc = {
    "time.struct_time",
    "The time value as returned by gmtime(), localtime(), and strptime(), and\n"
    " accepted by asctime(), mktime() and strftime().  May be considered as a\n"
    " sequence of 9 integers.\n\n"
    " Note that several fields' values are not the same as those defined by\n"
    " the C language standard for struct tm.  For example, the value of the\n"
    " field tm_year is the actual year, not year - 1900.  See individual\n"
    " fields' descriptions for details.",
    struct_time_type_fields,
    9,
};

#if defined(MS_WINDOWS)
#ifndef CREATE_WAITABLE_TIMER_HIGH_RESOLUTION
  #define CREATE_WAITABLE_TIMER_HIGH_RESOLUTION 0x00000002
#endif

static DWORD timer_flags = (DWORD)-1;
#endif

static PyObject *
tmtotuple(time_module_state *state, struct tm *p
#ifndef HAVE_STRUCT_TM_TM_ZONE
        , const char *zone, time_t gmtoff
#endif
)
{
    PyObject *v = PyStructSequence_New(state->struct_time_type);
    if (v == NULL)
        return NULL;

#define SET_ITEM(INDEX, CALL)                       \
    do {                                            \
        PyObject *obj = (CALL);                     \
        if (obj == NULL) {                          \
            Py_DECREF(v);                           \
            return NULL;                            \
        }                                           \
        PyStructSequence_SET_ITEM(v, (INDEX), obj); \
    } while (0)

#define SET(INDEX, VAL) \
    SET_ITEM((INDEX), PyLong_FromLong((long) (VAL)))

    SET(0, p->tm_year + 1900);
    SET(1, p->tm_mon + 1);         /* Want January == 1 */
    SET(2, p->tm_mday);
    SET(3, p->tm_hour);
    SET(4, p->tm_min);
    SET(5, p->tm_sec);
    SET(6, (p->tm_wday + 6) % 7); /* Want Monday == 0 */
    SET(7, p->tm_yday + 1);        /* Want January, 1 == 1 */
    SET(8, p->tm_isdst);
#ifdef HAVE_STRUCT_TM_TM_ZONE
    SET_ITEM(9, PyUnicode_DecodeLocale(p->tm_zone, "surrogateescape"));
    SET(10, p->tm_gmtoff);
#else
    SET_ITEM(9, PyUnicode_DecodeLocale(zone, "surrogateescape"));
    SET_ITEM(10, _PyLong_FromTime_t(gmtoff));
#endif /* HAVE_STRUCT_TM_TM_ZONE */

#undef SET
#undef SET_ITEM

    return v;
}

/* Parse arg tuple that can contain an optional float-or-None value;
   format needs to be "|O:name".
   Returns non-zero on success (parallels PyArg_ParseTuple).
*/
static int
parse_time_t_args(PyObject *args, const char *format, time_t *pwhen)
{
    PyObject *ot = NULL;
    time_t whent;

    if (!PyArg_ParseTuple(args, format, &ot))
        return 0;
    if (ot == NULL || ot == Py_None) {
        whent = time(NULL);
    }
    else {
        if (_PyTime_ObjectToTime_t(ot, &whent, _PyTime_ROUND_FLOOR) == -1)
            return 0;
    }
    *pwhen = whent;
    return 1;
}

static PyObject *
time_gmtime(PyObject *module, PyObject *args)
{
    time_t when;
    struct tm buf;

    if (!parse_time_t_args(args, "|O:gmtime", &when))
        return NULL;

    errno = 0;
    if (_PyTime_gmtime(when, &buf) != 0)
        return NULL;

    time_module_state *state = get_time_state(module);
#ifdef HAVE_STRUCT_TM_TM_ZONE
    return tmtotuple(state, &buf);
#else
    return tmtotuple(state, &buf, "UTC", 0);
#endif
}

#ifndef HAVE_TIMEGM
static time_t
timegm(struct tm *p)
{
    /* XXX: the following implementation will not work for tm_year < 1970.
       but it is likely that platforms that don't have timegm do not support
       negative timestamps anyways. */
    return p->tm_sec + p->tm_min*60 + p->tm_hour*3600 + p->tm_yday*86400 +
        (p->tm_year-70)*31536000 + ((p->tm_year-69)/4)*86400 -
        ((p->tm_year-1)/100)*86400 + ((p->tm_year+299)/400)*86400;
}
#endif

PyDoc_STRVAR(gmtime_doc,
"gmtime([seconds]) -> (tm_year, tm_mon, tm_mday, tm_hour, tm_min,\n\
                       tm_sec, tm_wday, tm_yday, tm_isdst)\n\
\n\
Convert seconds since the Epoch to a time tuple expressing UTC (a.k.a.\n\
GMT).  When 'seconds' is not passed in, convert the current time instead.\n\
\n\
If the platform supports the tm_gmtoff and tm_zone, they are available as\n\
attributes only.");

static PyObject *
time_localtime(PyObject *module, PyObject *args)
{
    time_t when;
    struct tm buf;

    if (!parse_time_t_args(args, "|O:localtime", &when))
        return NULL;
    if (_PyTime_localtime(when, &buf) != 0)
        return NULL;

    time_module_state *state = get_time_state(module);
#ifdef HAVE_STRUCT_TM_TM_ZONE
    return tmtotuple(state, &buf);
#else
    {
        struct tm local = buf;
        char zone[100];
        time_t gmtoff;
        strftime(zone, sizeof(zone), "%Z", &buf);
        gmtoff = timegm(&buf) - when;
        return tmtotuple(state, &local, zone, gmtoff);
    }
#endif
}

#if defined(__linux__) && !defined(__GLIBC__)
static const char *utc_string = NULL;
#endif

PyDoc_STRVAR(localtime_doc,
"localtime([seconds]) -> (tm_year,tm_mon,tm_mday,tm_hour,tm_min,\n\
                          tm_sec,tm_wday,tm_yday,tm_isdst)\n\
\n\
Convert seconds since the Epoch to a time tuple expressing local time.\n\
When 'seconds' is not passed in, convert the current time instead.");

/* Convert 9-item tuple to tm structure.  Return 1 on success, set
 * an exception and return 0 on error.
 */
static int
gettmarg(time_module_state *state, PyObject *args,
         struct tm *p, const char *format)
{
    int y;

    memset((void *) p, '\0', sizeof(struct tm));

    if (!PyTuple_Check(args)) {
        PyErr_SetString(PyExc_TypeError,
                        "Tuple or struct_time argument required");
        return 0;
    }

    if (!PyArg_ParseTuple(args, format,
                          &y, &p->tm_mon, &p->tm_mday,
                          &p->tm_hour, &p->tm_min, &p->tm_sec,
                          &p->tm_wday, &p->tm_yday, &p->tm_isdst))
        return 0;

    if (y < INT_MIN + 1900) {
        PyErr_SetString(PyExc_OverflowError, "year out of range");
        return 0;
    }

    p->tm_year = y - 1900;
    p->tm_mon--;
    p->tm_wday = (p->tm_wday + 1) % 7;
    p->tm_yday--;
#ifdef HAVE_STRUCT_TM_TM_ZONE
    if (Py_IS_TYPE(args, state->struct_time_type)) {
        PyObject *item;
        item = PyStructSequence_GET_ITEM(args, 9);
        if (item != Py_None) {
            p->tm_zone = (char *)PyUnicode_AsUTF8(item);
            if (p->tm_zone == NULL) {
                return 0;
            }
#if defined(__linux__) && !defined(__GLIBC__)
            // Make an attempt to return the C library's own timezone strings to
            // it. musl refuses to process a tm_zone field unless it produced
            // it. See issue #34672.
            if (utc_string && strcmp(p->tm_zone, utc_string) == 0) {
                p->tm_zone = utc_string;
            }
            else if (tzname[0] && strcmp(p->tm_zone, tzname[0]) == 0) {
                p->tm_zone = tzname[0];
            }
            else if (tzname[1] && strcmp(p->tm_zone, tzname[1]) == 0) {
                p->tm_zone = tzname[1];
            }
#endif
        }
        item = PyStructSequence_GET_ITEM(args, 10);
        if (item != Py_None) {
            p->tm_gmtoff = PyLong_AsLong(item);
            if (PyErr_Occurred())
                return 0;
        }
    }
#endif /* HAVE_STRUCT_TM_TM_ZONE */
    return 1;
}

/* Check values of the struct tm fields before it is passed to strftime() and
 * asctime().  Return 1 if all values are valid, otherwise set an exception
 * and returns 0.
 */
static int
checktm(struct tm* buf)
{
    /* Checks added to make sure strftime() and asctime() does not crash Python by
       indexing blindly into some array for a textual representation
       by some bad index (fixes bug #897625 and #6608).

       Also support values of zero from Python code for arguments in which
       that is out of range by forcing that value to the lowest value that
       is valid (fixed bug #1520914).

       Valid ranges based on what is allowed in struct tm:

       - tm_year: [0, max(int)] (1)
       - tm_mon: [0, 11] (2)
       - tm_mday: [1, 31]
       - tm_hour: [0, 23]
       - tm_min: [0, 59]
       - tm_sec: [0, 60]
       - tm_wday: [0, 6] (1)
       - tm_yday: [0, 365] (2)
       - tm_isdst: [-max(int), max(int)]

       (1) gettmarg() handles bounds-checking.
       (2) Python's acceptable range is one greater than the range in C,
       thus need to check against automatic decrement by gettmarg().
    */
    if (buf->tm_mon == -1)
        buf->tm_mon = 0;
    else if (buf->tm_mon < 0 || buf->tm_mon > 11) {
        PyErr_SetString(PyExc_ValueError, "month out of range");
        return 0;
    }
    if (buf->tm_mday == 0)
        buf->tm_mday = 1;
    else if (buf->tm_mday < 0 || buf->tm_mday > 31) {
        PyErr_SetString(PyExc_ValueError, "day of month out of range");
        return 0;
    }
    if (buf->tm_hour < 0 || buf->tm_hour > 23) {
        PyErr_SetString(PyExc_ValueError, "hour out of range");
        return 0;
    }
    if (buf->tm_min < 0 || buf->tm_min > 59) {
        PyErr_SetString(PyExc_ValueError, "minute out of range");
        return 0;
    }
    if (buf->tm_sec < 0 || buf->tm_sec > 61) {
        PyErr_SetString(PyExc_ValueError, "seconds out of range");
        return 0;
    }
    /* tm_wday does not need checking of its upper-bound since taking
    ``% 7`` in gettmarg() automatically restricts the range. */
    if (buf->tm_wday < 0) {
        PyErr_SetString(PyExc_ValueError, "day of week out of range");
        return 0;
    }
    if (buf->tm_yday == -1)
        buf->tm_yday = 0;
    else if (buf->tm_yday < 0 || buf->tm_yday > 365) {
        PyErr_SetString(PyExc_ValueError, "day of year out of range");
        return 0;
    }
    return 1;
}

#define STRFTIME_FORMAT_CODES \
"Commonly used format codes:\n\
\n\
%Y  Year with century as a decimal number.\n\
%m  Month as a decimal number [01,12].\n\
%d  Day of the month as a decimal number [01,31].\n\
%H  Hour (24-hour clock) as a decimal number [00,23].\n\
%M  Minute as a decimal number [00,59].\n\
%S  Second as a decimal number [00,61].\n\
%z  Time zone offset from UTC.\n\
%a  Locale's abbreviated weekday name.\n\
%A  Locale's full weekday name.\n\
%b  Locale's abbreviated month name.\n\
%B  Locale's full month name.\n\
%c  Locale's appropriate date and time representation.\n\
%I  Hour (12-hour clock) as a decimal number [01,12].\n\
%p  Locale's equivalent of either AM or PM.\n\
\n\
Other codes may be available on your platform.  See documentation for\n\
the C library strftime function.\n"

#ifdef HAVE_STRFTIME
#ifdef HAVE_WCSFTIME
#define time_char wchar_t
#define format_time wcsftime
#define time_strlen wcslen
#else
#define time_char char
#define format_time strftime
#define time_strlen strlen
#endif

static PyObject *
time_strftime1(time_char **outbuf, size_t *bufsize,
               time_char *format, size_t fmtlen,
               struct tm *tm)
{
    size_t buflen;
#if defined(MS_WINDOWS) && !defined(HAVE_WCSFTIME)
    /* check that the format string contains only valid directives */
    for (const time_char *f = strchr(format, '%');
        f != NULL;
        f = strchr(f + 2, '%'))
    {
        if (f[1] == '#')
            ++f; /* not documented by python, */
        if (f[1] == '\0')
            break;
        if ((f[1] == 'y') && tm->tm_year < 0) {
            PyErr_SetString(PyExc_ValueError,
                            "format %y requires year >= 1900 on Windows");
            return NULL;
        }
    }
#elif (defined(_AIX) || (defined(__sun) && defined(__SVR4))) && defined(HAVE_WCSFTIME)
    for (const time_char *f = wcschr(format, '%');
        f != NULL;
        f = wcschr(f + 2, '%'))
    {
        if (f[1] == L'\0')
            break;
        /* Issue #19634: On AIX, wcsftime("y", (1899, 1, 1, 0, 0, 0, 0, 0, 0))
           returns "0/" instead of "99" */
        if (f[1] == L'y' && tm->tm_year < 0) {
            PyErr_SetString(PyExc_ValueError,
                            "format %y requires year >= 1900 on AIX");
            return NULL;
        }
    }
#endif

    /* I hate these functions that presume you know how big the output
     * will be ahead of time...
     */
    while (1) {
        if (*bufsize > PY_SSIZE_T_MAX/sizeof(time_char)) {
            PyErr_NoMemory();
            return NULL;
        }
        *outbuf = (time_char *)PyMem_Realloc(*outbuf,
                                             *bufsize*sizeof(time_char));
        if (*outbuf == NULL) {
            PyErr_NoMemory();
            return NULL;
        }
#if defined _MSC_VER && _MSC_VER >= 1400 && defined(__STDC_SECURE_LIB__)
        errno = 0;
#endif
        _Py_BEGIN_SUPPRESS_IPH
        buflen = format_time(*outbuf, *bufsize, format, tm);
        _Py_END_SUPPRESS_IPH
#if defined _MSC_VER && _MSC_VER >= 1400 && defined(__STDC_SECURE_LIB__)
        /* VisualStudio .NET 2005 does this properly */
        if (buflen == 0 && errno == EINVAL) {
            PyErr_SetString(PyExc_ValueError, "Invalid format string");
            return NULL;
        }
#endif
        if (buflen == 0 && *bufsize < 256 * fmtlen) {
            *bufsize += *bufsize;
            continue;
        }
        /* If the buffer is 256 times as long as the format,
           it's probably not failing for lack of room!
           More likely, the format yields an empty result,
           e.g. an empty format, or %Z when the timezone
           is unknown. */
#ifdef HAVE_WCSFTIME
        return PyUnicode_FromWideChar(*outbuf, buflen);
#else
        return PyUnicode_DecodeLocaleAndSize(*outbuf, buflen, "surrogateescape");
#endif
    }
}

static PyObject *
time_strftime(PyObject *module, PyObject *args)
{
    PyObject *tup = NULL;
    struct tm buf;
    PyObject *format_arg;
    Py_ssize_t format_size;
    time_char *format, *outbuf = NULL;
    size_t fmtlen, bufsize = 1024;

    memset((void *) &buf, '\0', sizeof(buf));

    if (!PyArg_ParseTuple(args, "U|O:strftime", &format_arg, &tup))
        return NULL;

    time_module_state *state = get_time_state(module);
    if (tup == NULL) {
        time_t tt = time(NULL);
        if (_PyTime_localtime(tt, &buf) != 0)
            return NULL;
    }
    else if (!gettmarg(state, tup, &buf,
                       "iiiiiiiii;strftime(): illegal time tuple argument") ||
             !checktm(&buf))
    {
        return NULL;
    }

// Some platforms only support a limited range of years.
//
// Android works with negative years on the emulator, but fails on some
// physical devices (#123017).
#if defined(_MSC_VER) || (defined(__sun) && defined(__SVR4)) || defined(_AIX) \
    || defined(__VXWORKS__) || defined(__ANDROID__)
    if (buf.tm_year + 1900 < 1 || 9999 < buf.tm_year + 1900) {
        PyErr_SetString(PyExc_ValueError,
                        "strftime() requires year in [1; 9999]");
        return NULL;
    }
#endif

    /* Normalize tm_isdst just in case someone foolishly implements %Z
       based on the assumption that tm_isdst falls within the range of
       [-1, 1] */
    if (buf.tm_isdst < -1)
        buf.tm_isdst = -1;
    else if (buf.tm_isdst > 1)
        buf.tm_isdst = 1;

    format_size = PyUnicode_GET_LENGTH(format_arg);
    if ((size_t)format_size > PY_SSIZE_T_MAX/sizeof(time_char) - 1) {
        PyErr_NoMemory();
        return NULL;
    }
    format = PyMem_Malloc((format_size + 1)*sizeof(time_char));
    if (format == NULL) {
        PyErr_NoMemory();
        return NULL;
    }
    _PyUnicodeWriter writer;
    _PyUnicodeWriter_Init(&writer);
    writer.overallocate = 1;
    Py_ssize_t i = 0;
    while (i < format_size) {
        fmtlen = 0;
        for (; i < format_size; i++) {
            Py_UCS4 c = PyUnicode_READ_CHAR(format_arg, i);
            if (!c || c > 127) {
                break;
            }
            format[fmtlen++] = (char)c;
        }
        if (fmtlen) {
            format[fmtlen] = 0;
            PyObject *unicode = time_strftime1(&outbuf, &bufsize,
                                               format, fmtlen, &buf);
            if (unicode == NULL) {
                goto error;
            }
            if (_PyUnicodeWriter_WriteStr(&writer, unicode) < 0) {
                Py_DECREF(unicode);
                goto error;
            }
            Py_DECREF(unicode);
        }

        Py_ssize_t start = i;
        for (; i < format_size; i++) {
            Py_UCS4 c = PyUnicode_READ_CHAR(format_arg, i);
            if (c == '%') {
                break;
            }
        }
        if (_PyUnicodeWriter_WriteSubstring(&writer, format_arg, start, i) < 0) {
            goto error;
        }
    }

    PyMem_Free(outbuf);
    PyMem_Free(format);
    return _PyUnicodeWriter_Finish(&writer);
error:
    PyMem_Free(outbuf);
    PyMem_Free(format);
    _PyUnicodeWriter_Dealloc(&writer);
    return NULL;
}

#undef time_char
#undef format_time
PyDoc_STRVAR(strftime_doc,
"strftime(format[, tuple]) -> string\n\
\n\
Convert a time tuple to a string according to a format specification.\n\
See the library reference manual for formatting codes. When the time tuple\n\
is not present, current time as returned by localtime() is used.\n\
\n" STRFTIME_FORMAT_CODES);
#endif /* HAVE_STRFTIME */

static PyObject *
time_strptime(PyObject *self, PyObject *args)
{
    PyObject *func, *result;

    func = _PyImport_GetModuleAttrString("_strptime", "_strptime_time");
    if (!func) {
        return NULL;
    }

    result = PyObject_Call(func, args, NULL);
    Py_DECREF(func);
    return result;
}


PyDoc_STRVAR(strptime_doc,
"strptime(string, format) -> struct_time\n\
\n\
Parse a string to a time tuple according to a format specification.\n\
See the library reference manual for formatting codes (same as\n\
strftime()).\n\
\n" STRFTIME_FORMAT_CODES);

static PyObject *
_asctime(struct tm *timeptr)
{
    /* Inspired by Open Group reference implementation available at
     * http://pubs.opengroup.org/onlinepubs/009695399/functions/asctime.html */
    static const char wday_name[7][4] = {
        "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
    };
    static const char mon_name[12][4] = {
        "Jan", "Feb", "Mar", "Apr", "May", "Jun",
        "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
    };
    return PyUnicode_FromFormat(
        "%s %s%3d %.2d:%.2d:%.2d %d",
        wday_name[timeptr->tm_wday],
        mon_name[timeptr->tm_mon],
        timeptr->tm_mday, timeptr->tm_hour,
        timeptr->tm_min, timeptr->tm_sec,
        1900 + timeptr->tm_year);
}

static PyObject *
time_asctime(PyObject *module, PyObject *args)
{
    PyObject *tup = NULL;
    struct tm buf;

    if (!PyArg_UnpackTuple(args, "asctime", 0, 1, &tup))
        return NULL;

    time_module_state *state = get_time_state(module);
    if (tup == NULL) {
        time_t tt = time(NULL);
        if (_PyTime_localtime(tt, &buf) != 0)
            return NULL;
    }
    else if (!gettmarg(state, tup, &buf,
                       "iiiiiiiii;asctime(): illegal time tuple argument") ||
             !checktm(&buf))
    {
        return NULL;
    }
    return _asctime(&buf);
}

PyDoc_STRVAR(asctime_doc,
"asctime([tuple]) -> string\n\
\n\
Convert a time tuple to a string, e.g. 'Sat Jun 06 16:26:11 1998'.\n\
When the time tuple is not present, current time as returned by localtime()\n\
is used.");

static PyObject *
time_ctime(PyObject *self, PyObject *args)
{
    time_t tt;
    struct tm buf;
    if (!parse_time_t_args(args, "|O:ctime", &tt))
        return NULL;
    if (_PyTime_localtime(tt, &buf) != 0)
        return NULL;
    return _asctime(&buf);
}

PyDoc_STRVAR(ctime_doc,
"ctime(seconds) -> string\n\
\n\
Convert a time in seconds since the Epoch to a string in local time.\n\
This is equivalent to asctime(localtime(seconds)). When the time tuple is\n\
not present, current time as returned by localtime() is used.");

#ifdef HAVE_MKTIME
static PyObject *
time_mktime(PyObject *module, PyObject *tm_tuple)
{
    struct tm tm;
    time_t tt;

    time_module_state *state = get_time_state(module);
    if (!gettmarg(state, tm_tuple, &tm,
                  "iiiiiiiii;mktime(): illegal time tuple argument"))
    {
        return NULL;
    }

#if defined(_AIX) || (defined(__VXWORKS__) && !defined(_WRS_CONFIG_LP64))
    /* bpo-19748: AIX mktime() valid range is 00:00:00 UTC, January 1, 1970
       to 03:14:07 UTC, January 19, 2038. Thanks to the workaround below,
       it is possible to support years in range [1902; 2037] */
    if (tm.tm_year < 2 || tm.tm_year > 137) {
        /* bpo-19748: On AIX, mktime() does not report overflow error
           for timestamp < -2^31 or timestamp > 2**31-1. VxWorks has the
           same issue when working in 32 bit mode. */
        PyErr_SetString(PyExc_OverflowError,
                        "mktime argument out of range");
        return NULL;
    }
#endif

#ifdef _AIX
    /* bpo-34373: AIX mktime() has an integer overflow for years in range
       [1902; 1969]. Workaround the issue by using a year greater or equal than
       1970 (tm_year >= 70): mktime() behaves correctly in that case
       (ex: properly report errors). tm_year and tm_wday are adjusted after
       mktime() call. */
    int orig_tm_year = tm.tm_year;
    int delta_days = 0;
    while (tm.tm_year < 70) {
        /* Use 4 years to account properly leap years */
        tm.tm_year += 4;
        delta_days -= (366 + (365 * 3));
    }
#endif

    tm.tm_wday = -1;  /* sentinel; original value ignored */
    tt = mktime(&tm);

    /* Return value of -1 does not necessarily mean an error, but tm_wday
     * cannot remain set to -1 if mktime succeeded. */
    if (tt == (time_t)(-1)
        /* Return value of -1 does not necessarily mean an error, but
         * tm_wday cannot remain set to -1 if mktime succeeded. */
        && tm.tm_wday == -1)
    {
        PyErr_SetString(PyExc_OverflowError,
                        "mktime argument out of range");
        return NULL;
    }

#ifdef _AIX
    if (delta_days != 0) {
        tm.tm_year = orig_tm_year;
        if (tm.tm_wday != -1) {
            tm.tm_wday = (tm.tm_wday + delta_days) % 7;
        }
        tt += delta_days * (24 * 3600);
    }
#endif

    return PyFloat_FromDouble((double)tt);
}

PyDoc_STRVAR(mktime_doc,
"mktime(tuple) -> floating-point number\n\
\n\
Convert a time tuple in local time to seconds since the Epoch.\n\
Note that mktime(gmtime(0)) will not generally return zero for most\n\
time zones; instead the returned value will either be equal to that\n\
of the timezone or altzone attributes on the time module.");
#endif /* HAVE_MKTIME */

#ifdef HAVE_WORKING_TZSET
static int init_timezone(PyObject *module);

static PyObject *
time_tzset(PyObject *self, PyObject *unused)
{
    PyObject* m;

    m = PyImport_ImportModule("time");
    if (m == NULL) {
        return NULL;
    }

#if !defined(MS_WINDOWS) || defined(MS_WINDOWS_DESKTOP) || defined(MS_WINDOWS_SYSTEM)
    tzset();
#endif

    /* Reset timezone, altzone, daylight and tzname */
    if (init_timezone(m) < 0) {
         return NULL;
    }
    Py_DECREF(m);
    if (PyErr_Occurred())
        return NULL;

    Py_RETURN_NONE;
}

PyDoc_STRVAR(tzset_doc,
"tzset()\n\
\n\
Initialize, or reinitialize, the local timezone to the value stored in\n\
os.environ['TZ']. The TZ environment variable should be specified in\n\
standard Unix timezone format as documented in the tzset man page\n\
(eg. 'US/Eastern', 'Europe/Amsterdam'). Unknown timezones will silently\n\
fall back to UTC. If the TZ environment variable is not set, the local\n\
timezone is set to the systems best guess of wallclock time.\n\
Changing the TZ environment variable without calling tzset *may* change\n\
the local timezone used by methods such as localtime, but this behaviour\n\
should not be relied on.");
#endif /* HAVE_WORKING_TZSET */


static PyObject *
time_monotonic(PyObject *self, PyObject *unused)
{
    PyTime_t t;
    if (PyTime_Monotonic(&t) < 0) {
        return NULL;
    }
    return _PyFloat_FromPyTime(t);
}

PyDoc_STRVAR(monotonic_doc,
"monotonic() -> float\n\
\n\
Monotonic clock, cannot go backward.");

static PyObject *
time_monotonic_ns(PyObject *self, PyObject *unused)
{
    PyTime_t t;
    if (PyTime_Monotonic(&t) < 0) {
        return NULL;
    }
    return _PyTime_AsLong(t);
}

PyDoc_STRVAR(monotonic_ns_doc,
"monotonic_ns() -> int\n\
\n\
Monotonic clock, cannot go backward, as nanoseconds.");


static PyObject *
time_perf_counter(PyObject *self, PyObject *unused)
{
    PyTime_t t;
    if (PyTime_PerfCounter(&t) < 0) {
        return NULL;
    }
    return _PyFloat_FromPyTime(t);
}

PyDoc_STRVAR(perf_counter_doc,
"perf_counter() -> float\n\
\n\
Performance counter for benchmarking.");


static PyObject *
time_perf_counter_ns(PyObject *self, PyObject *unused)
{
    PyTime_t t;
    if (PyTime_PerfCounter(&t) < 0) {
        return NULL;
    }
    return _PyTime_AsLong(t);
}

PyDoc_STRVAR(perf_counter_ns_doc,
"perf_counter_ns() -> int\n\
\n\
Performance counter for benchmarking as nanoseconds.");


// gh-115714: Don't use times() on WASI.
#if defined(HAVE_TIMES) && !defined(__wasi__)
static int
process_time_times(time_module_state *state, PyTime_t *tp,
                   _Py_clock_info_t *info)
{
    _PyTimeFraction *base = &state->times_base;

    struct tms process;
    if (times(&process) == (clock_t)-1) {
        return 0;
    }

    if (info) {
        info->implementation = "times()";
        info->resolution = _PyTimeFraction_Resolution(base);
        info->monotonic = 1;
        info->adjustable = 0;
    }

    PyTime_t ns;
    ns = _PyTimeFraction_Mul(process.tms_utime, base);
    ns += _PyTimeFraction_Mul(process.tms_stime, base);
    *tp = ns;
    return 1;
}
#endif


static int
py_process_time(time_module_state *state, PyTime_t *tp,
                _Py_clock_info_t *info)
{
#if defined(MS_WINDOWS)
    HANDLE process;
    FILETIME creation_time, exit_time, kernel_time, user_time;
    ULARGE_INTEGER large;
    PyTime_t ktime, utime;
    BOOL ok;

    process = GetCurrentProcess();
    ok = GetProcessTimes(process, &creation_time, &exit_time,
                         &kernel_time, &user_time);
    if (!ok) {
        PyErr_SetFromWindowsErr(0);
        return -1;
    }

    if (info) {
        info->implementation = "GetProcessTimes()";
        info->resolution = 1e-7;
        info->monotonic = 1;
        info->adjustable = 0;
    }

    large.u.LowPart = kernel_time.dwLowDateTime;
    large.u.HighPart = kernel_time.dwHighDateTime;
    ktime = large.QuadPart;

    large.u.LowPart = user_time.dwLowDateTime;
    large.u.HighPart = user_time.dwHighDateTime;
    utime = large.QuadPart;

    /* ktime and utime have a resolution of 100 nanoseconds */
    *tp = (ktime + utime) * 100;
    return 0;
#else

    /* clock_gettime */
// gh-115714: Don't use CLOCK_PROCESS_CPUTIME_ID on WASI.
/* CLOCK_PROF is defined on NetBSD, but not supported.
 * CLOCK_PROCESS_CPUTIME_ID is broken on NetBSD for the same reason as
 * CLOCK_THREAD_CPUTIME_ID (see comment below).
 */
#if defined(HAVE_CLOCK_GETTIME) \
    && (defined(CLOCK_PROCESS_CPUTIME_ID) || defined(CLOCK_PROF)) \
    && !defined(__wasi__) \
    && !defined(__NetBSD__)
    struct timespec ts;

    if (HAVE_CLOCK_GETTIME_RUNTIME) {

#ifdef CLOCK_PROF
        const clockid_t clk_id = CLOCK_PROF;
        const char *function = "clock_gettime(CLOCK_PROF)";
#else
        const clockid_t clk_id = CLOCK_PROCESS_CPUTIME_ID;
        const char *function = "clock_gettime(CLOCK_PROCESS_CPUTIME_ID)";
#endif

        if (clock_gettime(clk_id, &ts) == 0) {
            if (info) {
                struct timespec res;
                info->implementation = function;
                info->monotonic = 1;
                info->adjustable = 0;
                if (clock_getres(clk_id, &res)) {
                    PyErr_SetFromErrno(PyExc_OSError);
                    return -1;
                }
                info->resolution = res.tv_sec + res.tv_nsec * 1e-9;
            }

            if (_PyTime_FromTimespec(tp, &ts) < 0) {
                return -1;
            }
            return 0;
        }
    }
#endif

    /* getrusage(RUSAGE_SELF) */
#if defined(HAVE_SYS_RESOURCE_H) && defined(HAVE_GETRUSAGE)
    struct rusage ru;

    if (getrusage(RUSAGE_SELF, &ru) == 0) {
        PyTime_t utime, stime;

        if (info) {
            info->implementation = "getrusage(RUSAGE_SELF)";
            info->monotonic = 1;
            info->adjustable = 0;
            info->resolution = 1e-6;
        }

        if (_PyTime_FromTimeval(&utime, &ru.ru_utime) < 0) {
            return -1;
        }
        if (_PyTime_FromTimeval(&stime, &ru.ru_stime) < 0) {
            return -1;
        }

        PyTime_t total = utime + stime;
        *tp = total;
        return 0;
    }
#endif

    /* times() */
// gh-115714: Don't use times() on WASI.
#if defined(HAVE_TIMES) && !defined(__wasi__)
    int res = process_time_times(state, tp, info);
    if (res < 0) {
        return -1;
    }
    if (res == 1) {
        return 0;
    }
    // times() failed, ignore failure
#endif

    /* clock(). Python 3 requires clock() to build (see gh-66814) */
    return py_clock(state, tp, info);
#endif
}

static PyObject *
time_process_time(PyObject *module, PyObject *unused)
{
    time_module_state *state = get_time_state(module);
    PyTime_t t;
    if (py_process_time(state, &t, NULL) < 0) {
        return NULL;
    }
    return _PyFloat_FromPyTime(t);
}

PyDoc_STRVAR(process_time_doc,
"process_time() -> float\n\
\n\
Process time for profiling: sum of the kernel and user-space CPU time.");

static PyObject *
time_process_time_ns(PyObject *module, PyObject *unused)
{
    time_module_state *state = get_time_state(module);
    PyTime_t t;
    if (py_process_time(state, &t, NULL) < 0) {
        return NULL;
    }
    return _PyTime_AsLong(t);
}

PyDoc_STRVAR(process_time_ns_doc,
"process_time() -> int\n\
\n\
Process time for profiling as nanoseconds:\n\
sum of the kernel and user-space CPU time.");


#if defined(MS_WINDOWS)
#define HAVE_THREAD_TIME
static int
_PyTime_GetThreadTimeWithInfo(PyTime_t *tp, _Py_clock_info_t *info)
{
    HANDLE thread;
    FILETIME creation_time, exit_time, kernel_time, user_time;
    ULARGE_INTEGER large;
    PyTime_t ktime, utime;
    BOOL ok;

    thread =  GetCurrentThread();
    ok = GetThreadTimes(thread, &creation_time, &exit_time,
                        &kernel_time, &user_time);
    if (!ok) {
        PyErr_SetFromWindowsErr(0);
        return -1;
    }

    if (info) {
        info->implementation = "GetThreadTimes()";
        info->resolution = 1e-7;
        info->monotonic = 1;
        info->adjustable = 0;
    }

    large.u.LowPart = kernel_time.dwLowDateTime;
    large.u.HighPart = kernel_time.dwHighDateTime;
    ktime = large.QuadPart;

    large.u.LowPart = user_time.dwLowDateTime;
    large.u.HighPart = user_time.dwHighDateTime;
    utime = large.QuadPart;

    /* ktime and utime have a resolution of 100 nanoseconds */
    *tp = (ktime + utime) * 100;
    return 0;
}

#elif defined(_AIX)
#define HAVE_THREAD_TIME
static int
_PyTime_GetThreadTimeWithInfo(PyTime_t *tp, _Py_clock_info_t *info)
{
    /* bpo-40192: On AIX, thread_cputime() is preferred: it has nanosecond
       resolution, whereas clock_gettime(CLOCK_THREAD_CPUTIME_ID)
       has a resolution of 10 ms. */
    thread_cputime_t tc;
    if (thread_cputime(-1, &tc) != 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }

    if (info) {
        info->implementation = "thread_cputime()";
        info->monotonic = 1;
        info->adjustable = 0;
        info->resolution = 1e-9;
    }
    *tp = (tc.stime + tc.utime);
    return 0;
}

#elif defined(__sun) && defined(__SVR4)
#define HAVE_THREAD_TIME
static int
_PyTime_GetThreadTimeWithInfo(PyTime_t *tp, _Py_clock_info_t *info)
{
    /* bpo-35455: On Solaris, CLOCK_THREAD_CPUTIME_ID clock is not always
       available; use gethrvtime() to substitute this functionality. */
    if (info) {
        info->implementation = "gethrvtime()";
        info->resolution = 1e-9;
        info->monotonic = 1;
        info->adjustable = 0;
    }
    *tp = gethrvtime();
    return 0;
}

/* CLOCK_THREAD_CPUTIME_ID is broken on NetBSD: the result of clock_gettime()
 * includes the sleeping time, that defeats the purpose of the clock.
 * Also, clock_getres() does not support it.
 * https://github.com/python/cpython/issues/123978
 * https://gnats.netbsd.org/57512
 */
#elif defined(HAVE_CLOCK_GETTIME) && \
      defined(CLOCK_THREAD_CPUTIME_ID) && \
      !defined(__EMSCRIPTEN__) && !defined(__wasi__) && \
      !defined(__NetBSD__)
#define HAVE_THREAD_TIME

#if defined(__APPLE__) && _Py__has_attribute(availability)
static int
_PyTime_GetThreadTimeWithInfo(PyTime_t *tp, _Py_clock_info_t *info)
     __attribute__((availability(macos, introduced=10.12)))
     __attribute__((availability(ios, introduced=10.0)))
     __attribute__((availability(tvos, introduced=10.0)))
     __attribute__((availability(watchos, introduced=3.0)));
#endif

static int
_PyTime_GetThreadTimeWithInfo(PyTime_t *tp, _Py_clock_info_t *info)
{
    struct timespec ts;
    const clockid_t clk_id = CLOCK_THREAD_CPUTIME_ID;
    const char *function = "clock_gettime(CLOCK_THREAD_CPUTIME_ID)";

    if (clock_gettime(clk_id, &ts)) {
        PyErr_SetFromErrno(PyExc_OSError);
        return -1;
    }
    if (info) {
        struct timespec res;
        info->implementation = function;
        info->monotonic = 1;
        info->adjustable = 0;
        if (clock_getres(clk_id, &res)) {
            PyErr_SetFromErrno(PyExc_OSError);
            return -1;
        }
        info->resolution = res.tv_sec + res.tv_nsec * 1e-9;
    }

    if (_PyTime_FromTimespec(tp, &ts) < 0) {
        return -1;
    }
    return 0;
}
#endif

#ifdef HAVE_THREAD_TIME
#ifdef __APPLE__
/*
 * The clock_* functions will be removed from the module
 * dict entirely when the C API is not available.
 */
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunguarded-availability"
#endif

static PyObject *
time_thread_time(PyObject *self, PyObject *unused)
{
    PyTime_t t;
    if (_PyTime_GetThreadTimeWithInfo(&t, NULL) < 0) {
        return NULL;
    }
    return _PyFloat_FromPyTime(t);
}

PyDoc_STRVAR(thread_time_doc,
"thread_time() -> float\n\
\n\
Thread time for profiling: sum of the kernel and user-space CPU time.");

static PyObject *
time_thread_time_ns(PyObject *self, PyObject *unused)
{
    PyTime_t t;
    if (_PyTime_GetThreadTimeWithInfo(&t, NULL) < 0) {
        return NULL;
    }
    return _PyTime_AsLong(t);
}

PyDoc_STRVAR(thread_time_ns_doc,
"thread_time() -> int\n\
\n\
Thread time for profiling as nanoseconds:\n\
sum of the kernel and user-space CPU time.");

#ifdef __APPLE__
#pragma clang diagnostic pop
#endif

#endif


static PyObject *
time_get_clock_info(PyObject *module, PyObject *args)
{
    char *name;
    _Py_clock_info_t info;
    PyObject *obj = NULL, *dict, *ns;
    PyTime_t t;

    if (!PyArg_ParseTuple(args, "s:get_clock_info", &name)) {
        return NULL;
    }

#ifdef Py_DEBUG
    info.implementation = NULL;
    info.monotonic = -1;
    info.adjustable = -1;
    info.resolution = -1.0;
#else
    info.implementation = "";
    info.monotonic = 0;
    info.adjustable = 0;
    info.resolution = 1.0;
#endif

    if (strcmp(name, "time") == 0) {
        if (_PyTime_TimeWithInfo(&t, &info) < 0) {
            return NULL;
        }
    }
    else if (strcmp(name, "monotonic") == 0) {
        if (_PyTime_MonotonicWithInfo(&t, &info) < 0) {
            return NULL;
        }
    }
    else if (strcmp(name, "perf_counter") == 0) {
        if (_PyTime_PerfCounterWithInfo(&t, &info) < 0) {
            return NULL;
        }
    }
    else if (strcmp(name, "process_time") == 0) {
        time_module_state *state = get_time_state(module);
        if (py_process_time(state, &t, &info) < 0) {
            return NULL;
        }
    }
#ifdef HAVE_THREAD_TIME
    else if (strcmp(name, "thread_time") == 0) {

#ifdef __APPLE__
        if (HAVE_CLOCK_GETTIME_RUNTIME) {
#endif
            if (_PyTime_GetThreadTimeWithInfo(&t, &info) < 0) {
                return NULL;
            }
#ifdef __APPLE__
        } else {
            PyErr_SetString(PyExc_ValueError, "unknown clock");
            return NULL;
        }
#endif
    }
#endif
    else {
        PyErr_SetString(PyExc_ValueError, "unknown clock");
        return NULL;
    }

    dict = PyDict_New();
    if (dict == NULL) {
        return NULL;
    }

    assert(info.implementation != NULL);
    obj = PyUnicode_FromString(info.implementation);
    if (obj == NULL) {
        goto error;
    }
    if (PyDict_SetItemString(dict, "implementation", obj) == -1) {
        goto error;
    }
    Py_CLEAR(obj);

    assert(info.monotonic != -1);
    obj = PyBool_FromLong(info.monotonic);
    if (obj == NULL) {
        goto error;
    }
    if (PyDict_SetItemString(dict, "monotonic", obj) == -1) {
        goto error;
    }
    Py_CLEAR(obj);

    assert(info.adjustable != -1);
    obj = PyBool_FromLong(info.adjustable);
    if (obj == NULL) {
        goto error;
    }
    if (PyDict_SetItemString(dict, "adjustable", obj) == -1) {
        goto error;
    }
    Py_CLEAR(obj);

    assert(info.resolution > 0.0);
    assert(info.resolution <= 1.0);
    obj = PyFloat_FromDouble(info.resolution);
    if (obj == NULL) {
        goto error;
    }
    if (PyDict_SetItemString(dict, "resolution", obj) == -1) {
        goto error;
    }
    Py_CLEAR(obj);

    ns = _PyNamespace_New(dict);
    Py_DECREF(dict);
    return ns;

error:
    Py_DECREF(dict);
    Py_XDECREF(obj);
    return NULL;
}

PyDoc_STRVAR(get_clock_info_doc,
"get_clock_info(name: str) -> dict\n\
\n\
Get information of the specified clock.");

#ifndef HAVE_DECL_TZNAME
static void
get_zone(char *zone, int n, struct tm *p)
{
#ifdef HAVE_STRUCT_TM_TM_ZONE
    strncpy(zone, p->tm_zone ? p->tm_zone : "   ", n);
#else
    tzset();
    strftime(zone, n, "%Z", p);
#endif
}

static time_t
get_gmtoff(time_t t, struct tm *p)
{
#ifdef HAVE_STRUCT_TM_TM_ZONE
    return p->tm_gmtoff;
#else
    return timegm(p) - t;
#endif
}
#endif // !HAVE_DECL_TZNAME

static int
init_timezone(PyObject *m)
{
#define ADD_INT(NAME, VALUE) do {                       \
    if (PyModule_AddIntConstant(m, NAME, VALUE) < 0) {  \
        return -1;                                      \
    }                                                   \
} while (0)

    assert(!PyErr_Occurred());

    /* This code moved from PyInit_time wholesale to allow calling it from
    time_tzset. In the future, some parts of it can be moved back
    (for platforms that don't HAVE_WORKING_TZSET, when we know what they
    are), and the extraneous calls to tzset(3) should be removed.
    I haven't done this yet, as I don't want to change this code as
    little as possible when introducing the time.tzset and time.tzsetwall
    methods. This should simply be a method of doing the following once,
    at the top of this function and removing the call to tzset() from
    time_tzset():

        #ifdef HAVE_TZSET
        tzset()
        #endif

    And I'm lazy and hate C so nyer.
     */
#ifdef HAVE_DECL_TZNAME
    PyObject *otz0, *otz1;
#if !defined(MS_WINDOWS) || defined(MS_WINDOWS_DESKTOP) || defined(MS_WINDOWS_SYSTEM)
    tzset();
#endif
    ADD_INT("timezone", _Py_timezone);
#ifdef HAVE_ALTZONE
    ADD_INT("altzone", altzone);
#else
    ADD_INT("altzone", _Py_timezone-3600);
#endif
    ADD_INT("daylight", _Py_daylight);
#ifdef MS_WINDOWS
    TIME_ZONE_INFORMATION tzinfo = {0};
    GetTimeZoneInformation(&tzinfo);
    otz0 = PyUnicode_FromWideChar(tzinfo.StandardName, -1);
    if (otz0 == NULL) {
        return -1;
    }
    otz1 = PyUnicode_FromWideChar(tzinfo.DaylightName, -1);
    if (otz1 == NULL) {
        Py_DECREF(otz0);
        return -1;
    }
#else
    otz0 = PyUnicode_DecodeLocale(_Py_tzname[0], "surrogateescape");
    if (otz0 == NULL) {
        return -1;
    }
    otz1 = PyUnicode_DecodeLocale(_Py_tzname[1], "surrogateescape");
    if (otz1 == NULL) {
        Py_DECREF(otz0);
        return -1;
    }
#endif // MS_WINDOWS
    if (PyModule_Add(m, "tzname", Py_BuildValue("(NN)", otz0, otz1)) < 0) {
        return -1;
    }
#else // !HAVE_DECL_TZNAME
    static const time_t YEAR = (365 * 24 + 6) * 3600;
    time_t t;
    struct tm p;
    time_t janzone_t, julyzone_t;
    char janname[10], julyname[10];
    t = (time((time_t *)0) / YEAR) * YEAR;
    _PyTime_localtime(t, &p);
    get_zone(janname, 9, &p);
    janzone_t = -get_gmtoff(t, &p);
    janname[9] = '\0';
    t += YEAR/2;
    _PyTime_localtime(t, &p);
    get_zone(julyname, 9, &p);
    julyzone_t = -get_gmtoff(t, &p);
    julyname[9] = '\0';

    /* Sanity check, don't check for the validity of timezones.
       In practice, it should be more in range -12 hours .. +14 hours. */
#define MAX_TIMEZONE (48 * 3600)
    if (janzone_t < -MAX_TIMEZONE || janzone_t > MAX_TIMEZONE
        || julyzone_t < -MAX_TIMEZONE || julyzone_t > MAX_TIMEZONE)
    {
        PyErr_SetString(PyExc_RuntimeError, "invalid GMT offset");
        return -1;
    }
    int janzone = (int)janzone_t;
    int julyzone = (int)julyzone_t;

    PyObject *tzname_obj;
    if (janzone < julyzone) {
        /* DST is reversed in the southern hemisphere */
        ADD_INT("timezone", julyzone);
        ADD_INT("altzone", janzone);
        ADD_INT("daylight", janzone != julyzone);
        tzname_obj = Py_BuildValue("(zz)", julyname, janname);
    } else {
        ADD_INT("timezone", janzone);
        ADD_INT("altzone", julyzone);
        ADD_INT("daylight", janzone != julyzone);
        tzname_obj = Py_BuildValue("(zz)", janname, julyname);
    }
    if (PyModule_Add(m, "tzname", tzname_obj) < 0) {
        return -1;
    }
#endif // !HAVE_DECL_TZNAME
#undef ADD_INT

    if (PyErr_Occurred()) {
        return -1;
    }
    return 0;
}


// Include Argument Clinic code after defining converters such as
// time_clockid_converter().
#include "clinic/timemodule.c.h"

static PyMethodDef time_methods[] = {
    {"time",            time_time, METH_NOARGS, time_doc},
    {"time_ns",         time_time_ns, METH_NOARGS, time_ns_doc},
#ifdef HAVE_CLOCK_GETTIME
    TIME_CLOCK_GETTIME_METHODDEF
    TIME_CLOCK_GETTIME_NS_METHODDEF
#endif
#ifdef HAVE_CLOCK_SETTIME
    {"clock_settime",   time_clock_settime, METH_VARARGS, clock_settime_doc},
    {"clock_settime_ns",time_clock_settime_ns, METH_VARARGS, clock_settime_ns_doc},
#endif
#ifdef HAVE_CLOCK_GETRES
    {"clock_getres",    time_clock_getres, METH_VARARGS, clock_getres_doc},
#endif
#ifdef HAVE_PTHREAD_GETCPUCLOCKID
    {"pthread_getcpuclockid", time_pthread_getcpuclockid, METH_VARARGS, pthread_getcpuclockid_doc},
#endif
    {"sleep",           time_sleep, METH_O, sleep_doc},
    {"gmtime",          time_gmtime, METH_VARARGS, gmtime_doc},
    {"localtime",       time_localtime, METH_VARARGS, localtime_doc},
    {"asctime",         time_asctime, METH_VARARGS, asctime_doc},
    {"ctime",           time_ctime, METH_VARARGS, ctime_doc},
#ifdef HAVE_MKTIME
    {"mktime",          time_mktime, METH_O, mktime_doc},
#endif
#ifdef HAVE_STRFTIME
    {"strftime",        time_strftime, METH_VARARGS, strftime_doc},
#endif
    {"strptime",        time_strptime, METH_VARARGS, strptime_doc},
#ifdef HAVE_WORKING_TZSET
    {"tzset",           time_tzset, METH_NOARGS, tzset_doc},
#endif
    {"monotonic",       time_monotonic, METH_NOARGS, monotonic_doc},
    {"monotonic_ns",    time_monotonic_ns, METH_NOARGS, monotonic_ns_doc},
    {"process_time",    time_process_time, METH_NOARGS, process_time_doc},
    {"process_time_ns", time_process_time_ns, METH_NOARGS, process_time_ns_doc},
#ifdef HAVE_THREAD_TIME
    {"thread_time",     time_thread_time, METH_NOARGS, thread_time_doc},
    {"thread_time_ns",  time_thread_time_ns, METH_NOARGS, thread_time_ns_doc},
#endif
    {"perf_counter",    time_perf_counter, METH_NOARGS, perf_counter_doc},
    {"perf_counter_ns", time_perf_counter_ns, METH_NOARGS, perf_counter_ns_doc},
    {"get_clock_info",  time_get_clock_info, METH_VARARGS, get_clock_info_doc},
    {NULL,              NULL}           /* sentinel */
};


PyDoc_STRVAR(module_doc,
"This module provides various functions to manipulate time values.\n\
\n\
There are two standard representations of time.  One is the number\n\
of seconds since the Epoch, in UTC (a.k.a. GMT).  It may be an integer\n\
or a floating-point number (to represent fractions of seconds).\n\
The epoch is the point where the time starts, the return value of time.gmtime(0).\n\
It is January 1, 1970, 00:00:00 (UTC) on all platforms.\n\
\n\
The other representation is a tuple of 9 integers giving local time.\n\
The tuple items are:\n\
  year (including century, e.g. 1998)\n\
  month (1-12)\n\
  day (1-31)\n\
  hours (0-23)\n\
  minutes (0-59)\n\
  seconds (0-59)\n\
  weekday (0-6, Monday is 0)\n\
  Julian day (day in the year, 1-366)\n\
  DST (Daylight Savings Time) flag (-1, 0 or 1)\n\
If the DST flag is 0, the time is given in the regular time zone;\n\
if it is 1, the time is given in the DST time zone;\n\
if it is -1, mktime() should guess based on the date and time.\n");


static int
time_exec(PyObject *module)
{
    time_module_state *state = get_time_state(module);
#if defined(__APPLE__) && defined(HAVE_CLOCK_GETTIME)
    if (HAVE_CLOCK_GETTIME_RUNTIME) {
        /* pass: ^^^ cannot use '!' here */
    } else {
        PyObject* dct = PyModule_GetDict(module);
        if (dct == NULL) {
            return -1;
        }

        if (PyDict_PopString(dct, "clock_gettime", NULL) < 0) {
            return -1;
        }
        if (PyDict_PopString(dct, "clock_gettime_ns", NULL) < 0) {
            return -1;
        }
        if (PyDict_PopString(dct, "clock_settime", NULL) < 0) {
            return -1;
        }
        if (PyDict_PopString(dct, "clock_settime_ns", NULL) < 0) {
            return -1;
        }
        if (PyDict_PopString(dct, "clock_getres", NULL) < 0) {
            return -1;
        }
    }
#endif
#if defined(__APPLE__) && defined(HAVE_THREAD_TIME)
    if (HAVE_CLOCK_GETTIME_RUNTIME) {
        /* pass: ^^^ cannot use '!' here */
    } else {
        PyObject* dct = PyModule_GetDict(module);

        if (PyDict_PopString(dct, "thread_time", NULL) < 0) {
            return -1;
        }
        if (PyDict_PopString(dct, "thread_time_ns", NULL) < 0) {
            return -1;
        }
    }
#endif
    /* Set, or reset, module variables like time.timezone */
    if (init_timezone(module) < 0) {
        return -1;
    }

#if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_CLOCK_SETTIME) || defined(HAVE_CLOCK_GETRES)
    if (HAVE_CLOCK_GETTIME_RUNTIME) {

#ifdef CLOCK_REALTIME
        if (PyModule_AddIntMacro(module, CLOCK_REALTIME) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_MONOTONIC
        if (PyModule_AddIntMacro(module, CLOCK_MONOTONIC) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_MONOTONIC_RAW
        if (PyModule_AddIntMacro(module, CLOCK_MONOTONIC_RAW) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_HIGHRES
        if (PyModule_AddIntMacro(module, CLOCK_HIGHRES) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_PROCESS_CPUTIME_ID
        if (PyModule_AddIntMacro(module, CLOCK_PROCESS_CPUTIME_ID) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_THREAD_CPUTIME_ID
        if (PyModule_AddIntMacro(module, CLOCK_THREAD_CPUTIME_ID) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_PROF
        if (PyModule_AddIntMacro(module, CLOCK_PROF) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_BOOTTIME
        if (PyModule_AddIntMacro(module, CLOCK_BOOTTIME) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_TAI
        if (PyModule_AddIntMacro(module, CLOCK_TAI) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_UPTIME
        if (PyModule_AddIntMacro(module, CLOCK_UPTIME) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_UPTIME_RAW
        if (PyModule_AddIntMacro(module, CLOCK_UPTIME_RAW) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_MONOTONIC_RAW_APPROX
        if (PyModule_AddIntMacro(module, CLOCK_MONOTONIC_RAW_APPROX) < 0) {
            return -1;
        }
#endif
#ifdef CLOCK_UPTIME_RAW_APPROX
        if (PyModule_AddIntMacro(module, CLOCK_UPTIME_RAW_APPROX) < 0) {
            return -1;
        }
#endif
    }

#endif  /* defined(HAVE_CLOCK_GETTIME) || defined(HAVE_CLOCK_SETTIME) || defined(HAVE_CLOCK_GETRES) */

    if (PyModule_AddIntConstant(module, "_STRUCT_TM_ITEMS", 11)) {
        return -1;
    }

    // struct_time type
    state->struct_time_type = PyStructSequence_NewType(&struct_time_type_desc);
    if (state->struct_time_type == NULL) {
        return -1;
    }
    if (PyModule_AddType(module, state->struct_time_type)) {
        return -1;
    }

#if defined(__linux__) && !defined(__GLIBC__)
    struct tm tm;
    const time_t zero = 0;
    if (gmtime_r(&zero, &tm) != NULL)
        utc_string = tm.tm_zone;
#endif

#if defined(MS_WINDOWS)
    if (timer_flags == (DWORD)-1) {
        DWORD test_flags = CREATE_WAITABLE_TIMER_HIGH_RESOLUTION;
        HANDLE timer = CreateWaitableTimerExW(NULL, NULL, test_flags,
                                              TIMER_ALL_ACCESS);
        if (timer == NULL) {
            // CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is not supported.
            timer_flags = 0;
        }
        else {
            // CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is supported.
            timer_flags = CREATE_WAITABLE_TIMER_HIGH_RESOLUTION;
            CloseHandle(timer);
        }
    }
#endif

// gh-115714: Don't use times() on WASI.
#if defined(HAVE_TIMES) && !defined(__wasi__)
    long ticks_per_second;
    if (_Py_GetTicksPerSecond(&ticks_per_second) < 0) {
        PyErr_SetString(PyExc_RuntimeError,
                        "cannot read ticks_per_second");
        return -1;
    }
    if (_PyTimeFraction_Set(&state->times_base, SEC_TO_NS,
                            ticks_per_second) < 0) {
        PyErr_Format(PyExc_OverflowError, "ticks_per_second is too large");
        return -1;
    }
#endif

#ifdef HAVE_CLOCK
    if (_PyTimeFraction_Set(&state->clock_base, SEC_TO_NS,
                            CLOCKS_PER_SEC) < 0) {
        PyErr_Format(PyExc_OverflowError, "CLOCKS_PER_SEC is too large");
        return -1;
    }
#endif

    return 0;
}


static int
time_module_traverse(PyObject *module, visitproc visit, void *arg)
{
    time_module_state *state = get_time_state(module);
    Py_VISIT(state->struct_time_type);
    return 0;
}


static int
time_module_clear(PyObject *module)
{
    time_module_state *state = get_time_state(module);
    Py_CLEAR(state->struct_time_type);
    return 0;
}


static void
time_module_free(void *module)
{
    time_module_clear((PyObject *)module);
}


static struct PyModuleDef_Slot time_slots[] = {
    {Py_mod_exec, time_exec},
    {Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
    {Py_mod_gil, Py_MOD_GIL_NOT_USED},
    {0, NULL}
};

static struct PyModuleDef timemodule = {
    PyModuleDef_HEAD_INIT,
    .m_name = "time",
    .m_doc = module_doc,
    .m_size = sizeof(time_module_state),
    .m_methods = time_methods,
    .m_slots = time_slots,
    .m_traverse = time_module_traverse,
    .m_clear = time_module_clear,
    .m_free = time_module_free,
};

PyMODINIT_FUNC
PyInit_time(void)
{
    return PyModuleDef_Init(&timemodule);
}


// time.sleep() implementation.
// On error, raise an exception and return -1.
// On success, return 0.
static int
pysleep(PyTime_t timeout)
{
    assert(timeout >= 0);

#ifndef MS_WINDOWS
#ifdef HAVE_CLOCK_NANOSLEEP
    struct timespec timeout_abs;
#elif defined(HAVE_NANOSLEEP)
    struct timespec timeout_ts;
#else
    struct timeval timeout_tv;
#endif
    PyTime_t deadline, monotonic;
    int err = 0;

    if (PyTime_Monotonic(&monotonic) < 0) {
        return -1;
    }
    deadline = monotonic + timeout;
#ifdef HAVE_CLOCK_NANOSLEEP
    if (_PyTime_AsTimespec(deadline, &timeout_abs) < 0) {
        return -1;
    }
#endif

    do {
#ifdef HAVE_CLOCK_NANOSLEEP
        // use timeout_abs
#elif defined(HAVE_NANOSLEEP)
        if (_PyTime_AsTimespec(timeout, &timeout_ts) < 0) {
            return -1;
        }
#else
        if (_PyTime_AsTimeval(timeout, &timeout_tv, _PyTime_ROUND_CEILING) < 0) {
            return -1;
        }
#endif

        int ret;
        Py_BEGIN_ALLOW_THREADS
#ifdef HAVE_CLOCK_NANOSLEEP
        ret = clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &timeout_abs, NULL);
        err = ret;
#elif defined(HAVE_NANOSLEEP)
        ret = nanosleep(&timeout_ts, NULL);
        err = errno;
#else
        ret = select(0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &timeout_tv);
        err = errno;
#endif
        Py_END_ALLOW_THREADS

        if (ret == 0) {
            break;
        }

        if (err != EINTR) {
            errno = err;
            PyErr_SetFromErrno(PyExc_OSError);
            return -1;
        }

        /* sleep was interrupted by SIGINT */
        if (PyErr_CheckSignals()) {
            return -1;
        }

#ifndef HAVE_CLOCK_NANOSLEEP
        if (PyTime_Monotonic(&monotonic) < 0) {
            return -1;
        }
        timeout = deadline - monotonic;
        if (timeout < 0) {
            break;
        }
        /* retry with the recomputed delay */
#endif
    } while (1);

    return 0;
#else  // MS_WINDOWS
    PyTime_t timeout_100ns = _PyTime_As100Nanoseconds(timeout,
                                                       _PyTime_ROUND_CEILING);

    // Maintain Windows Sleep() semantics for time.sleep(0)
    if (timeout_100ns == 0) {
        Py_BEGIN_ALLOW_THREADS
        // A value of zero causes the thread to relinquish the remainder of its
        // time slice to any other thread that is ready to run. If there are no
        // other threads ready to run, the function returns immediately, and
        // the thread continues execution.
        Sleep(0);
        Py_END_ALLOW_THREADS
        return 0;
    }

    LARGE_INTEGER relative_timeout;
    // No need to check for integer overflow, both types are signed
    assert(sizeof(relative_timeout) == sizeof(timeout_100ns));
    // SetWaitableTimer(): a negative due time indicates relative time
    relative_timeout.QuadPart = -timeout_100ns;

    HANDLE timer = CreateWaitableTimerExW(NULL, NULL, timer_flags,
                                          TIMER_ALL_ACCESS);
    if (timer == NULL) {
        PyErr_SetFromWindowsErr(0);
        return -1;
    }

    if (!SetWaitableTimerEx(timer, &relative_timeout,
                            0, // no period; the timer is signaled once
                            NULL, NULL, // no completion routine
                            NULL,  // no wake context; do not resume from suspend
                            0)) // no tolerable delay for timer coalescing
    {
        PyErr_SetFromWindowsErr(0);
        goto error;
    }

    // Only the main thread can be interrupted by SIGINT.
    // Signal handlers are only executed in the main thread.
    if (_PyOS_IsMainThread()) {
        HANDLE sigint_event = _PyOS_SigintEvent();

        while (1) {
            // Check for pending SIGINT signal before resetting the event
            if (PyErr_CheckSignals()) {
                goto error;
            }
            ResetEvent(sigint_event);

            HANDLE events[] = {timer, sigint_event};
            DWORD rc;

            Py_BEGIN_ALLOW_THREADS
            rc = WaitForMultipleObjects(Py_ARRAY_LENGTH(events), events,
                                        // bWaitAll
                                        FALSE,
                                        // No wait timeout
                                        INFINITE);
            Py_END_ALLOW_THREADS

            if (rc == WAIT_FAILED) {
                PyErr_SetFromWindowsErr(0);
                goto error;
            }

            if (rc == WAIT_OBJECT_0) {
                // Timer signaled: we are done
                break;
            }

            assert(rc == (WAIT_OBJECT_0 + 1));
            // The sleep was interrupted by SIGINT: restart sleeping
        }
    }
    else {
        DWORD rc;

        Py_BEGIN_ALLOW_THREADS
        rc = WaitForSingleObject(timer, INFINITE);
        Py_END_ALLOW_THREADS

        if (rc == WAIT_FAILED) {
            PyErr_SetFromWindowsErr(0);
            goto error;
        }

        assert(rc == WAIT_OBJECT_0);
        // Timer signaled: we are done
    }

    CloseHandle(timer);
    return 0;

error:
    CloseHandle(timer);
    return -1;
#endif
}