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bpo-41299: QueryPerformanceFrequency() cannot fail (GH-28552)

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py_win_perf_counter_frequency() no longer checks for
QueryPerformanceFrequency() failure. According to the
QueryPerformanceFrequency() documentation, the function can no longer
fails since Windows XP.
This commit is contained in:
Victor Stinner 2021-09-25 00:31:56 +02:00 • committed by GitHub
parent 7c801e0fa6
commit f35ddf2422
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1 changed files with 7 additions and 21 deletions
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28
Python/pytime.c
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@ -1050,26 +1050,14 @@ py_win_perf_counter_frequency(LONGLONG *pfrequency, int raise)
LONGLONG frequency; LONGLONG frequency;
LARGE_INTEGER freq; LARGE_INTEGER freq;
if (!QueryPerformanceFrequency(&freq)) { // Since Windows XP, the function cannot fail.
if (raise) { (void)QueryPerformanceFrequency(&freq);
PyErr_SetFromWindowsErr(0);
}
return -1;
}
frequency = freq.QuadPart; frequency = freq.QuadPart;
/* Sanity check: should never occur in practice */ // Since Windows XP, frequency cannot be zero.
if (frequency < 1) { assert(frequency >= 1);
if (raise) {
PyErr_SetString(PyExc_RuntimeError,
"invalid QueryPerformanceFrequency");
}
return -1;
}
/* Check that frequency can be casted to _PyTime_t. /* Make also sure that (ticks * SEC_TO_NS) cannot overflow in
Make also sure that (ticks * SEC_TO_NS) cannot overflow in
_PyTime_MulDiv(), with ticks < frequency. _PyTime_MulDiv(), with ticks < frequency.
Known QueryPerformanceFrequency() values: Known QueryPerformanceFrequency() values:
@ -1078,10 +1066,8 @@ py_win_perf_counter_frequency(LONGLONG *pfrequency, int raise)
* 3,579,545 Hz (3.6 MHz): 279 ns resolution * 3,579,545 Hz (3.6 MHz): 279 ns resolution
None of these frequencies can overflow with 64-bit _PyTime_t, but None of these frequencies can overflow with 64-bit _PyTime_t, but
check for overflow, just in case. */ check for integer overflow just in case. */
if (frequency > _PyTime_MAX if (frequency > _PyTime_MAX / SEC_TO_NS) {
|| frequency > (LONGLONG)_PyTime_MAX / (LONGLONG)SEC_TO_NS)
{
if (raise) { if (raise) {
PyErr_SetString(PyExc_OverflowError, PyErr_SetString(PyExc_OverflowError,
"QueryPerformanceFrequency is too large"); "QueryPerformanceFrequency is too large");