Time Functions
The following functions are used with system time.
| Function | Description |
|---|---|
| GetSystemTime | Retrieves the current system date and time in UTC format. |
| GetSystemTimeAdjustment | Determines whether the system is applying periodic time adjustments to its time-of-day clock. |
| GetTimeFormat | Formats a system time as a time string for a specified locale. |
| NtQuerySystemTime | Returns the system time. |
| RtlLocalTimeToSystemTime | Converts the specified local time to system time. |
| RtlTimeToSecondsSince1970 | Converts the specified system time to the number of seconds since the first second of January 1, 1970. |
| SetSystemTime | Sets the current system time and date. |
| SetSystemTimeAdjustment | Enables or disables periodic time adjustments to the system's time-of-day clock. |
| SystemTimeToFileTime | Converts a system time to a file time. |
| SystemTimeToTzSpecificLocalTime | Converts a UTC time to a specified time zone's corresponding local time. |
| TzSpecificLocalTimeToSystemTime | Converts a local time to a UTC time. |
The following functions are used with local time.
| Function | Description |
|---|---|
| EnumDynamicTimeZoneInformation | Enumerates dynamic daylight saving time information entries stored in the registry. |
| FileTimeToLocalFileTime | Converts a UTC file time to a local file time. |
| GetDynamicTimeZoneInformation | Retrieves the current time zone and dynamic daylight saving time settings. |
| GetDynamicTimeZoneInformationEffectiveYears | Retrieves a range, expressed in years, for which a DYNAMIC_TIME_ZONE_INFORMATION has valid entries. |
| GetLocalTime | Retrieves the current local date and time. |
| GetTimeZoneInformation | Retrieves the current time zone settings. |
| GetTimeZoneInformationForYear | Retrieves the time zone settings for the specified year and time zone. |
| RtlLocalTimeToSystemTime | Converts the specified local time to system time. |
| SetDynamicTimeZoneInformation | Sets the current time zone and dynamic daylight saving time settings. |
| SetLocalTime | Sets the current local time and date. |
| SetTimeZoneInformation | Sets the current time zone settings. |
| SystemTimeToTzSpecificLocalTime | Converts a UTC time to a specified time zone's corresponding local time. |
| SystemTimeToTzSpecificLocalTimeEx | Converts a UTC time with dynamic daylight saving time settings to a specified time zone's corresponding local time. |
| TzSpecificLocalTimeToSystemTime | Converts a local time to a UTC time. |
| TzSpecificLocalTimeToSystemTimeEx | Converts a local time with dynamic daylight saving time settings to UTC time. |
The following functions are used with file time.
| Function | Description |
|---|---|
| CompareFileTime | Compares two file times. |
| FileTimeToLocalFileTime | Converts a UTC file time to a local file time. |
| FileTimeToSystemTime | Converts a file time to system time format. |
| GetFileTime | Retrieves the date and time that the specified file or directory was created, last accessed, and last modified. |
| GetSystemTimeAsFileTime | Retrieves the current system date and time in UTC format. |
| LocalFileTimeToFileTime | Converts a local file time to a file time based on UTC. |
| SetFileTime | Sets the date and time that the specified file or directory was created, last accessed, or last modified. |
| SystemTimeToFileTime | Converts a system time to a file time. |
The following functions are used with MS-DOS date and time.
| Function | Description |
|---|---|
| DosDateTimeToFileTime | Converts MS-DOS date and time values to a file time. |
| FileTimeToDosDateTime | Converts a file time to MS-DOS date and time values. |
The following functions are used with Windows time.
| Function | Description |
|---|---|
| GetSystemTimes | Retrieves system timing information. |
| GetTickCount | Retrieves the number of milliseconds that have elapsed since the system was started, up to 49.7 days. |
| GetTickCount64 | Retrieves the number of milliseconds that have elapsed since the system was started. |
The following functions are used with high-resolution performance counters.
| Function | Description |
|---|---|
| QueryPerformanceCounter | Retrieves the current value of the high-resolution performance counter. |
| QueryPerformanceFrequency | Retrieves the frequency of the high-resolution performance counter. |
The following functions are used with the auxiliary performance counter.
| Function | Description |
|---|---|
| QueryAuxiliaryCounterFrequency | Queries the auxiliary counter frequency. |
| ConvertAuxiliaryCounterToPerformanceCounter | Converts the specified auxiliary counter value to the corresponding performance counter value; optionally provides the estimated conversion error in nanoseconds due to latencies and maximum possible drift. |
| ConvertPerformanceCounterToAuxiliaryCounter | Converts the specified performance counter value to the corresponding auxiliary counter value; optionally provides the estimated conversion error in nanoseconds due to latencies and maximum possible drift. |
The following function is used with interrupt time.
| Function | Description |
|---|---|
| QueryInterruptTime | Gets the current interrupt-time count. |
| QueryInterruptTimePrecise | Gets the current interrupt-time count, in a more precise form than QueryInterruptTime does. |
| QueryUnbiasedInterruptTime | Gets the current unbiased interrupt-time count. The unbiased interrupt-time count does not include time the system spends in sleep or hibernation. |
| QueryUnbiasedInterruptTimePrecise | Gets the current unbiased interrupt-time count, in a more precise form than QueryUnbiasedInterruptTime does. The unbiased interrupt-time count does not include time the system spends in sleep or hibernation. |