I came from Here. My question is specifically about getting environment variables updates from a different session. If I update the system environment variable in one user session, I found the other sessions must log out/in to apply the change. But if I just run SET in other sessions, I can see the change. But any new process won't pick up the change.
Is this behavior by design? Is there a way for other users to get the new environment variable without logging off?
There is a system-level API call "SendMessageTimeout " that can be PInvoked using PowerShell:
Invoke-WMSettingsChange
http://poshcode.org/2049
Description: Notifies other processes that the global environment block has changed. This lets other processes pick changes to ENV: without having to reboot or logoff/logon. A non-zero result from SendMessageTimeout indicates success.
if (-not ("win32.nativemethods" -as [type])) {
# import sendmessagetimeout from win32
add-type -Namespace Win32 -Name NativeMethods -MemberDefinition @"
[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
public static extern IntPtr SendMessageTimeout(
IntPtr hWnd, uint Msg, UIntPtr wParam, string lParam,
uint fuFlags, uint uTimeout, out UIntPtr lpdwResult);
"@
}
$HWND_BROADCAST = [intptr]0xffff;
$WM_SETTINGCHANGE = 0x1a;
$result = [uintptr]::zero
# notify all windows of environment block change
[win32.nativemethods]::SendMessageTimeout($HWND_BROADCAST, $WM_SETTINGCHANGE,
[uintptr]::Zero, "Environment", 2, 5000, [ref]$result);
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