Merge pull request #30943 from ibrahn/fix-win-gettime-aliasing

Fix strict-aliasing warning in OS_Windows::get_unix_time.
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Rémi Verschelde 2019-07-30 09:26:36 +02:00 committed by GitHub
commit 71dbe398df
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1 changed files with 10 additions and 2 deletions

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@ -2252,9 +2252,17 @@ uint64_t OS_Windows::get_unix_time() const {
FILETIME fep;
SystemTimeToFileTime(&ep, &fep);
// FIXME: dereferencing type-punned pointer will break strict-aliasing rules (GCC warning)
// Type punning through unions (rather than pointer cast) as per:
// https://docs.microsoft.com/en-us/windows/desktop/api/minwinbase/ns-minwinbase-filetime#remarks
return (*(uint64_t *)&ft - *(uint64_t *)&fep) / 10000000;
ULARGE_INTEGER ft_punning;
ft_punning.LowPart = ft.dwLowDateTime;
ft_punning.HighPart = ft.dwHighDateTime;
ULARGE_INTEGER fep_punning;
fep_punning.LowPart = fep.dwLowDateTime;
fep_punning.HighPart = fep.dwHighDateTime;
return (ft_punning.QuadPart - fep_punning.QuadPart) / 10000000;
};
uint64_t OS_Windows::get_system_time_secs() const {