Problem with inputDevices.llb\Aquire Input Data.vi after CTRL-ALT-DEL

[DavidJCrawford]

I was building a vi to poll for key presses in dynamically loaded test vi's. I wanted to experiment with the Input Device Control vi's to achieve this. It was for simple operations like the ESCAPE, SPACE, C for CONTINUE, A to ABORT, Any Key To Continue etc.

If the vi is run with an empty array of desired keys to poll so any key can be used. I then pressed CTRL-ALT-DEL to get to the Task Manager. When I closed the task manager I found that the keyboard buffer always has DECIMAL and L ALT. So the polling loop always finds a key and stops immediately.

This is looking like a bug to me. If anyone else can help to verify it or has any advice then that would be appreciated.

Labview 7.1, Full Dev, WinXP.

[JonBowers]

Hi David,

I have had a look at the vi that you attached to your post and I was able to reproduce the problem. However I don't think it is an actual bug but more the way that the windows API deals with CTRL-ALT-DEL commands. Windows uses these commands to lock out other applications and I think it keeps the keys as modifiers. As the API we use to get the keyboard states isn't very sofisticated this doesn't reset these modifiers. If before you run the vi again you press CTRL ALT and DEL separately it resets them and they don't show up when you run the vi again.

Regards

Jonathan

[DavidJCrawford]

Hi Jonathan

Nice one! You are dead right about the toggle behaviour. Thats gets me back on track.

many thanks

David