About This Article
This article was created using an automated generation workflow leveraging generative AI. It reviews the Microsoft Win32 API GetLastInputInfo specification and organizes a minimal test case using P/Invoke from PowerShell to observe the elapsed time since the last input.
Verification Status: 📘 Confirmed with official Microsoft documentation, unverified on a physical Windows device.
By calling Win32 GetLastInputInfo from PowerShell, you can observe how long there has been no keyboard or mouse input based on the timestamp of the last input event.
This test is successful if IdleSeconds can be retrieved as a numerical value.
Smoke Test
Add-Type @'
using System;
using System.Runtime.InteropServices;
public static class InputIdle {
[StructLayout(LayoutKind.Sequential)]
public struct LASTINPUTINFO { public uint cbSize; public uint dwTime; }
[DllImport("user32.dll")]
public static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);
}
'@
$lii = New-Object InputIdle+LASTINPUTINFO
$lii.cbSize = [Runtime.InteropServices.Marshal]::SizeOf($lii)
if ([InputIdle]::GetLastInputInfo([ref]$lii)) {
$now32 = [uint32]([Environment]::TickCount64 -band 0xFFFFFFFFL)
$idleMs = [uint32]($now32 - $lii.dwTime)
"[SUCCESS] IdleSeconds = {0:N1}" -f ($idleMs / 1000)
} else {
$code = [Runtime.InteropServices.Marshal]::GetLastWin32Error()
"[FAILED] GetLastInputInfo returned false. Win32Error=$code"
}
Observe
After checking the value, leave the mouse and keyboard untouched for a few seconds and run it again. Then, move the mouse and run it again to see if the value drops back down.
Why This Data Can Be Retrieved
Windows retains timestamp information for input events, and this API returns the last input information for the current session. This does not serve as proof of attendance or "the time the individual was actively working."
dwTimeSince
Try Changing One Thing
Change the display unit from seconds to minutes.
$idleMs / 60000
In the Daily-Code-Samples version, this can be toggled using -Unit Seconds / -Unit Minutes, allowing you to also check the original milliseconds, LastInputTick, and CurrentTick32.
Failures and Edge Cases
You need to be mindful of sessions, tick count handling, and type conversion. If the API returns false, do not treat it as a success and display the Win32 error as well. It is also important not to overinterpret the values for monitoring purposes.
If Used in Production
It can be used as an auxiliary check in personal local tools, such as "initiating heavy automated processing if there is no input for a certain period." Examples include auxiliary conditions before starting local processing of large CSV files, or experiments with display switching on demonstration terminals.
On the other hand, do not casually repurpose this for employee monitoring or attendance tracking. A lack of input is not synonymous with not working, and this API does not prove actual work activity.
Official Information
- Microsoft Learn: GetLastInputInfo function
