Issue #25155: Add _PyTime_AsTimevalTime_t() function

On Windows, the tv_sec field of the timeval structure has the type C long,
whereas it has the type C time_t on all other platforms. A C long has a size of
32 bits (signed inter, 1 bit for the sign, 31 bits for the value) which is not
enough to store an Epoch timestamp after the year 2038.

Add the _PyTime_AsTimevalTime_t() function written for datetime.datetime.now():
convert a _PyTime_t timestamp to a (secs, us) tuple where secs type is time_t.
It allows to support dates after the year 2038 on Windows.

Enhance also _PyTime_AsTimeval_impl() to detect overflow on the number of
seconds when rounding the number of microseconds.

1 files changed, 12 insertions, 0 deletions

diff --git a/Include/pytime.h b/Include/pytime.h
index 027c3d8..494322c 100644
--- a/Include/pytime.h
+++ b/Include/pytime.h
@@ -117,6 +117,18 @@ PyAPI_FUNC(int) _PyTime_AsTimeval_noraise(_PyTime_t t,
     struct timeval *tv,
     _PyTime_round_t round);
 
+/* Convert a timestamp to a number of seconds (secs) and microseconds (us).
+   us is always positive. This function is similar to _PyTime_AsTimeval()
+   except that secs is always a time_t type, whereas the timeval structure
+   uses a C long for tv_sec on Windows.
+   Raise an exception and return -1 if the conversion overflowed,
+   return 0 on success. */
+PyAPI_FUNC(int) _PyTime_AsTimevalTime_t(
+    _PyTime_t t,
+    time_t *secs,
+    int *us,
+    _PyTime_round_t round);
+
 #if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_KQUEUE)
 /* Convert a timestamp to a timespec structure (nanosecond resolution).
    tv_nsec is always positive.