I am trying to write up a C++ program for a class using XCode. One of the things I wish to do, is to simply clear the screen. I've looked into how to do this, however the catch is that the code needs to run on both a Windows and Macintosh computer. I've looked at some other similar questions, but none of the answers help me. I know there is no "screen" but I want the system to clear the output window. I know that the command system("clear"); does what I want it to, but when XCode tests the program, instead of clearing the screen it prints TERM Variable not set
I've tried opening up the terminal and typing clear and it does in fact respond the way I want it to, so why doesn't the 'terminal' inside of XCode do the same? I just want to get the output window in XCode to respond to clear the same way that the terminal already does.
Here is something I have already tried;
I went to the terminal and ran echo $TERM, to which the terminal responded xterm-256color. I then went over to XCode and opened the "Scheme" settings, and found an Environment Variables setting under "Arguments". I added a variable (to the blank list) called TERM and gave it value xterm-256color. Upon running the program again, the output displays ¿[H¿[2J in the output window, positioned where the TERM Variable not set used to be printed.
Last thing, as a reminder, I cannot change the source code from the way it is now, or it could cause errors when the program is run on a Windows machine.
It does not work because you are "lying": The terminal in Xcode is not a xterm-256color, but it is dumb terminal. More precise, the display represents a NSTextStorage that collects stdout and/or (depending on target switch) stderr.
A dumb terminal is not able to clean the display. If you want to change this, you can write a plug-in similar to Xcode-Colors what adds the ability to understand ansi color codes.
However, if your requirement that the code simply run at Windows and OSX, you may stick with your solution system("clear"), since it works prefectly in the "normal" OSX terminal.
Related
Years ago, when I last had call to use GDB to debug a Linux server, I seem to remember seeing a listing of the code that was being executed. Perhaps it was just the current line +/- five lines or so. I think i also remember it redrawing the entire console, every time I executed a command, so that the code listing was always at the top of the screen.
Now that I am once again in need of GDB's assistance, is my memory playing cruel tricks on me? Or does such a mode actually exist?
The documentation I'm finding online just points me at the 'l' command to list code. That looks like it has some potential, but there doesn't seem to be a way to get it to dynamically update as I step/next my way through the code.
If it's significant, I'm running Ubuntu on a dedicated Linux machine, and (since the program uses OpenGL) the actual debugging is going on inside a Weston Compositor terminal window.
I'm used to using Xcode for my C++ class homework. I usually just create a command line project, write code, and test it with the console that appears at the bottom of the window. But since I updated Xcode (it's now 8.3.1), I can't make the console appear when I run my command line app. This question seems to have come up before, and I followed the instructions here, but the console is weird. For example, I wrote a simple function, and then the main program. The console wouldn't do anything until I first typed a number, and then it used my input as the parameter for the function. That's not how it's supposed to work. The console didn't give the prompt or anything. The main program worked, but only because I knew the program. Someone else who didn't know how it worked would simply see a blank console.
I have a C++ program that runs nicely and it gives my output in the terminal when it runs, this is handy if the algorithm takes time.
How do I 'cout' the output in a terminal styled div in the browser (doesn't allow user to type into it as an actual terminal)
Alternatively is there a different C++ command to direct output elsewhere other than the terminal window in which it is currently running?
Kind of new to C++ so maybe this is a obvious fix but thanks anyway
We've been struggling for a while now to understand the keyboard scancode behavior in Linux.
When we open a normal bash shell, the arrow keys works as expected: UP shows the previous item in the history etc. However when you spawn a process, arrows does not work as expected anymore. For example, UP prints ^[[A instead of the previous command.
To demonstrate this, do something like:
bash$ ping www.google.com
Now, press UP or DOWN etc. and you will see the wrongly mapped key codes while the process is running. However, when you terminate the process the arrow keys will work again.
We've tested it on CentOs, Ubuntu, Mac and even in different shells (bash, sh, zsh) and the same happens everywhere. I've also tried different keyboard modes using kbd_mode where we tested with RAW and XLATE modes.
The closest thing I could see while searching for answers were IPython users have experienced the same behavior when IPython was not build against readline. However, this is not related to our case as far as I can see.
We are developing a C++ Tcl based console application which uses cin and cout to communicate with, and get input from the user. We are having issues with the arrow keys when we try to access the history of previously entered commands. This is a major issue for us as 99% of people expects the arrow characters to just work.
Any ideas on how we could overcome this would be much appreciated.
You must set the terminal into raw mode to get the scan codes and handle them (that is: disable ICANON, you want the non-canonical mode). You probably also want to disable ECHO (so that it doesn't print your input on the terminal).
That is what readline or linenoise are doing. See here for some code. Esp. see the function linenoiseEnableRawMode. Some other simple sample Python code is here where I have written a simple console media player which checks for the keypresses left ("\x1b[D") and right ("\x1b[C").
The relevant calls are to tcgetattr (to get the current terminal state and modify that state struct to get into raw mode and enable some other useful behavior stuff) and tcsetattr (to set the state).
readline, libedit or linenoise are some libraries which do all that work for you and provide you with history, autocompletion, etc.
At the end, you must restore back the old state, otherwise you get the behavior you are describing in your shell.
As you can see in u413.com: Text comes on the screen, letter by letter, which looks kind of cool,
I want to do the same thing in Console
I got the source code of version 1.2; because I dont need all the complexity of version 2;
I just need a simple Command Prompt, with text that comes on to the screen letter by letter.
I dont need most of the builtin functions offered by Console, like Transparency, Taskbar Icon, etc.
The source code base is pretty small with only about 5 files.
The main class file seems to be Console.cpp;
Since console is like a GUI application, things dont get written to the STDOUT.
but heres what happens;
A Handle is called;
And that handle apparently writes to the console;
m_hStdOut = ::GetStdHandle(STD_OUTPUT_HANDLE);
Now what I want to be able to do; Is somehow read the handle; see what text it has; And throw in a loop with a ::Sleep(20) method in it; to make sure that text appears letter by letter.
#Alf P. Steinbach I wrote the psuedo code for making the sleep command(in java) I also made use of it in every other java program I wrote, but the disadvantage was that it will work only for my programs and not every program run in the command prompt, but what I dont know is code to make a console, a windows console subsystem program, I wish it was possible with java, so that I could use it on linux too, but now, let me ask you exactly what I had in mind...
A program which simply, took input from the screen, send it to cmd.exe for processing, and sent back the reply, and all I have to do is throw in a sleep command between every character...
All I need is help, in getting this done, I wish you could start me up with this, and possible provide links and refrences to get this done...
This Console.cpp seems like a console emulator, meaning it runs OTHER programs. You don't need the source code, you can run existing console applications.
STD_INPUT_HANDLE, STD_OUTPUT_HANDLE and STD_ERROR_HANDLE are the windows handles for STDIN, STDOUT and STDERR. They basicly does the same with only a few differences in how to use it.
If you want to integrate the console into your code, then you have to understand it, and find its own output function and call that. But it won't be any standard handle or things like that.