I have attempted several approaches to clearing the screen in C, under Cygwin. system("cls") and system("clear") don't work when the application is running, giving errors that say in effect, "that command doesn't exist". I'm testing a c application that is going to end up on a micro-controller and operate an LCD screen, and the testing code needs to output the monochrome LCD data to the console each time it changes. The state changes have the potential to occur very quickly, and visualizing the changes properly really means I need an honest-to-goodness screen clear to occur in a programmatic way. Any ideas how this might be done?
Related
I asked this question in the Raspberry PI section, so please forgive me for posting this here again. Its just there doesn't seem to be as active as this section of the forum. So, onto my question...
I have an idea and I'm working on it right now. I just wanted to see what the community's thought was on using a screensaver as digital signage. Every tutorial I've read shows someone using chromium in kiosk mode, and while that's fine and works well for some uses, it doesn't work for what I need. I have successfully completed a chromium kiosk, and it was cool. But the signage that I need to create now, has to work without internet. I've thought about installing LAMP locally on the PI, and still using chromium. I still may have to if this idea doesn't pan out. All I need from the signage is a Title Message in the top center, and a message body underneath it, with roughly 300-400 character limit. My idea is to write a screensaver module, in C, that will work with a screensaver such as xscreensaver. The module would need to be able to load messages from a directory on the pi. Then for my clients to update their signage text, I would write a simple client that sent commands as well as the text via SSH to the pi. I want to know what other people think about this. Is it a good idea? Bad idea? Should I "waste" my time doing something like this?
Thanks in advance.
I am already using a rPi as digital signage, just over a year. I am using two different setups:
version 1 uses Raspian loading xdesktop and qiv image viewer to cycle images stored on the Pi itself, synchronized with a remote server. The problem I found was power and SD stability, when the power fails, which it will do no matter what, just when... The Sd card can become corrupt due to all the writing that Raspian does all the time. Certainly does not really need to write to SD.
version 2 uses a RO-filesystem and a command line image tool. Uses the same process to show images from local, and sync with server. But power fail causes no ill effects.
I am not using screensaver to display images, that seemed redundant to me, and unnecessary to wait for the SS to start just to display the images.
Some of the images are created using imagemagik, which is nicely dynamic where needed.
I have an arduino in keyboard emulation mode that sends keyboard keystrokes to the computer it's connected to, the latter appending a log line in a local webpage upon receiving each keystroke. The log program is coded in C using Win32 API.
Now, since it's supposed to function at work (the idea is to get a log file online of when pushbuttons on my desk have been activated), I will be locking my computer...
How can I keep processing CTRL+ALT+key strokes from the windows lock screen?
Thanks,
Mister Mystère
This seems to work: https://www.codeproject.com/Articles/19004/A-Simple-C-Global-Low-Level-Keyboard-Hook
When you run the compiled executable, the keys A and B are detected globally even when the screen is locked.
I ended up downloading a third party lock screen and my program works in its background as it is a standard program. For those of you in the same situation, as far as I know after all that research I'm afraid you'll have to do that instead: it seems like it is not possible starting from Vista.
I am currently creating a c program that counts all of the keys I press in a day and sorts the key types by amount, so I can tell which ones I press most often. It was more of a side project than anything else but I have become annoyed with the fact that my program doesn't seem to be able to intercept any input to password fields. I suppose this is a good thing, but I have been spending hours looking at documentation and trying to figure how to do this. I am not trying to create any sort of malicious software. Is there a way around this? My program is running as root. I am using the ApplicationServices framework and CGEventRef and the CGEventTapCreate funcion. Should I be using a different framework or struct? Also, is there a difference between kCGHIDEventTap, kCGSessionEventTap, and kCGAnnotatedSessionEventTap? I have tried using each of them and it does not seem to make a difference in my program.
I am running this on OS X 10.9
UPDATE
Apparently I cannot capture keystrokes going to terminal either, which is where I spend most of my time on my laptop. This is a problem.
What you want is fairly complicated and requires a kernel extension. The interprocess communication is also not trivial. Take a look at logKext, specifically logKext.cpp. That project actually logs the keystrokes to an encrypted file. You should be able to pull everything you need from it.
This scenario has come up before and I'm wondering if there is any way I can determine where the actively running form is executing within code? The problem is when I inherit a very large application which I'm not totally familiar with yet and I have it running through VS.NET 2010. I might have a particular screen up and go "geeze it would be nice if I could start debugging when I do 'x'".
If this was a simple form with some buttons I wouldn't even bother asking here; I'm not that novice. But the time consuming task is when I look at a tabbed screen in a large multi-project solution with drag and drop capabilities, right click options, etc. and have to spend 5-10 minutes tracking down where to place a breakpoint to debug.
What I'm wondering is if there is a way to have the WinForms app running via IDE and do 'something' that tells VS.NET on the next action break into the code (obviously without a breakpoint because I don't know where to place one yet). This would save me a ton of time trying to track down which event is occurring in a not so simple form or series of forms.
I hope this makes sense...
Thanks!
Yes, that's somewhat possible. When you use Debug + Break All then the 99.9% odds are that you don't break into code that's part of the project. A Winforms app is normally idle, pumping the message loop and waiting for Windows to tell it that something happened. You'll break at the Application.Run() statement.
The trick to then use Debug + Step Over. The program resumes running like normal. Then give a UI command (do 'x' in your question) and the debugger will break at the first statement of real code, typically at the start of the event handler for that command. It isn't exactly guaranteed that that code would be relevant, you might break at a MouseMove event handler for example. So YMMV.
I am developing a C program that prints out a message. The problem with it is that when I run its .exe file, it does not run in fullscreen (until I press alt+enter to force it to full screen). I want the program to run in fullscreen itself when I run it. Is there any way I can do it?
Thanks in advance.
You could call SetConsoleDisplayMode() to force CONSOLE_FULLSCREEN_MODE. Beware that support for this has been disappearing. The last machine I owned that could still do this has been gathering dust for quite a while already. Along with the memory of the loud relay clicking sound, mixed with the high-pitched wail of the flyback transformer in the CRT.