STINNER Victor <vstin...@python.org> added the comment:
_PyTime_FromDouble() checks if!(_Py_DoubleInIntegralTypeRange(_PyTime_t, d)) with the macro: #define _Py_InIntegralTypeRange(type, v) (_Py_IntegralTypeMin(type) <= v && v <= _Py_IntegralTypeMax(type)) and _Py_IntegralTypeMax(type)=2**63-1. "v <= _Py_IntegralTypeMax(type)" compares a C double to a C int64_t: the compiler casts the C int64_t to a C double. The problem is that 2**63-1 casted to a C double rounds using ROUND_HALF_EVEN rounding mode which gives a number *greater* than 2**63-1: we get 2**63. To implement "v <= max", we have to round max towards zero (ROUND_DOWN), not round it using ROUND_HALF_EVEN. I didn't find a way to control the rounding mode of casting C int64_t to C double, but we can round it *afterwards* using nextafter(max, 0.0) (ROUND_DOWN). ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue39277> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
