PoQueryWatchdogTime function (ntifs.h)
The PoQueryWatchdogTime routine indicates whether the power manager has enabled a watchdog time-out counter for any power IRP that is currently assigned to the device stack.
Syntax
BOOLEAN PoQueryWatchdogTime(
[in] PDEVICE_OBJECT Pdo,
[out] PULONG SecondsRemaining
);
Parameters
[in] Pdo
A pointer to a physical device object (PDO). This parameter points to a DEVICE_OBJECT structure that represents a physical device.
[out] SecondsRemaining
A pointer to a location into which the routine writes the time, in seconds, that remains before the next power watchdog time-out is set to occur.
Return value
PoQueryWatchdogTime returns TRUE if a watchdog-enabled power IRP is currently assigned to the device stack. Otherwise, it returns FALSE.
Remarks
This routine enables kernel-mode drivers to monitor watchdog time-out counters that the power manager has enabled to keep track of power IRPs that it has issued. If one or more watchdog time-out counters are currently enabled, the routine returns TRUE and provides the amount of time that remains before the next time-out.
For example, a driver that experiences delays when shutting down a device can call this routine to determine how much time remains before the driver must respond to a power IRP to prevent a controlled shutdown (a bug check) of the operating system.
The power manager sets a watchdog time-out counter when it issues a power IRP to the device stack. The time-out period for this counter is typically several minutes. If a device in the stack is unresponsive and causes the IRP to stall for the time-out period, the power manager treats this condition as an unrecoverable error and initiates a controlled shutdown of the operating system.
If more than one power watchdog time-out is currently enabled, the routine sets *SecondsRemaining to the time that remains to the next time-out.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 7 |
| Target Platform | Universal |
| Header | ntifs.h (include Wdm.h, Ntddk.h, Ntifs.h) |
| Library | NtosKrnl.lib |
| DLL | NtosKrnl.exe |
| IRQL | <= DISPATCH_LEVEL |