In Matlab or GNU Octave, this command input("") allows to break the input process by pressing CTRL+C or CTRL+Z. Is there a way to block this, so that only a valid input is accepted?
Note: Pressing CTRL+Z on an input command even exits the Octave shell in a Linux terminal, so I understand that the control must be established at a different layer.
So you want input to ignore when Ctrl + C is pushed? I don't think that's possible simply because this could potentially be dangerous. Ignoring listening to Ctrl + C could open the possibility of your code running endlessly and you not being able to break out of the code unless you manually kill MATLAB. I'm not saying that what you desire with input will be dangerous, but if MATLAB allowed you to ignore this keystroke in any capacity, then you'd have that dangerous situation that I talked about if used improperly.
FWIW, check out this link on MATLAB Central: http://www.mathworks.com/matlabcentral/answers/25213-disabling-ctrl-c-in-a-gui . Here, someone is trying to ignore Ctrl + C so that their GUI doesn't needlessly crash, but MathWorks confirms that it is not possible to do so.
Related
In Matlab I can start external .exe files that sometime have a pop up that requires an enter key pressed. For example:
system('C:\Program Files (x86)\WinZip\WINZIP32.EXE')
will start Winzip, and then in order to use it you need to pass the "buy now" pop up window by pressing enter.
Now my problem is not with winzip, I only gave it as an example (i use winrar anyway :).
How can I programmatically press an enter key in Matlab in such cases ? (I use win 7)
Can an event listener be used to solve that?
EDIT: The java.awt.Robot class indeed works on explorer, but not on any software that has a pop up window with an OK button that needs to be pressed. I don't know why it doesn't work for that. I gave the winzip example because I assume everybody has winzip/winrar installed in their machine. The actual software I have is different and irrelevant for the question.
There is a way using Java from Matlab, specifically the java.awt.Robot class. See here.
Apparently there are two types of programs, regarding the way they work when called from Matlab with system('...'):
For some programs, Matlab waits until the program has finished before running the next statement. This happens for example with WinRAR (at least in my Windows 7 machine).
For other programs this doesn't happen, and Matlab proceeds with the next statement right after the external program has been started. An example of this type is explorer (the standard Windows file explorer).
Now, it is possible to return execution to Matlab immediately even for type 1 programs: just add & at the end of the string passed to system. This is standard in Linux Bash shell, and it also works in Windows, as discussed here.
So, you would proceed as follows:
robot = java.awt.Robot;
command = '"C:\Program Files (x86)\WinRAR\WinRAR"'; %// external program; full path
system([command ' &']); %// note: ' &' at the end
pause(5) %// allow some time for the external program to start
robot.keyPress (java.awt.event.KeyEvent.VK_ENTER); %// press "enter" key
robot.keyRelease (java.awt.event.KeyEvent.VK_ENTER); %// release "enter" key
If your applications are only on Windows platform, you can try using .net objects.
The SendWait method of the SendKeys objects allows to send virtually any key, or key combination, to the application which has the focus, including the "modifier" keys like Alt, Shift, Ctrl etc ...
The first thing to do is to import the .net library, then the full syntax to send the ENTER key would be:
NET.addAssembly('System.Windows.Forms');
System.Windows.Forms.SendKeys.SendWait('{ENTER}'); %// send the key "ENTER"
If you only do it once the full syntax is OK. If you plan to make extensive use of the command, you can help yourself with an anonymous helper function.
A little example with notepad
%% // import the .NET assembly and define helper function
NET.addAssembly('System.Windows.Forms');
sendkey = #(strkey) System.Windows.Forms.SendKeys.SendWait(strkey) ;
%% // prepare a few things to send to the notepad
str1 = 'Hello World' ;
str2 = 'OMG ... my notepad is alive' ;
file2save = [pwd '\SelfSaveTest.txt'] ;
if exist(file2save,'file')==2 ; delete(file2save) ; end %// this is just in case you run the test multiple times.
%% // go for it
%// write a few things, save the file then close it.
system('notepad &') ; %// Start notepad, without matlab waiting for the return value
sendkey(str1) %// send a full string to the notepad
sendkey('{ENTER}'); %// send the {ENTER} key
sendkey(str2) %// send another full string to the notepad
sendkey('{! 3}'); %// note how you can REPEAT a key send instruction
sendkey('%(FA)'); %// Send key combination to open the "save as..." dialog
pause(1) %// little pause to make sure your hard drive is ready before continuing
sendkey(file2save); %// Send the name (full path) of the file to save to the dialog
sendkey('{ENTER}'); %// validate
pause(3) %// just wait a bit so you can see you file is now saved (check the titlebar of the notepad)
sendkey('%(FX)'); %// Bye bye ... close the Notepad
As explained in the Microsoft documentation the SendKeys class may have some timing issues sometimes so if you want to do complex manipulations (like Tab multiple times to change the button you actually want to press), you may have to introduce a pause in your Matlab calls to SendKeys.
Try without first, but don't forget you are managing a process from another without any synchronization between them, so timing all that can require a bit of trial and error before you get it right, at least for complex sequences (simple one should be straightforward).
In my case above for example I am running all my data from an external hard drive with an ECO function which puts it into standby, so when I called the "save as..." dialog, it takes time for it to display because the HDD has to wake up. If I didn't introduce the pause(1), sometimes the file path would be imcomplete (the first part of the path was send before the dialog had the focus).
Also, do not forget the & character when you execute the external program. All credit to Luis Mendo for highlighting it. (I tend to forget how important it is because I use it by default. I only omit it if I have to specifically wait for a return value from the program, otherwise I let it run on its own)
The special characters have a special code. Here are a few:
Shift +
Control (Ctrl) ^
Alt %
Tab {TAB}
Backspace {BACKSPACE}, {BS}, or {BKSP}
Validation {ENTER} or ~ (a tilde)
Ins Or Insert {INSERT} or {INS}
Delete {DELETE} or {DEL}
Text Navigation {HOME} {END} {PGDN} {PGUP}
Arrow Keys {UP} {RIGHT} {DOWN} {LEFT}
Escape {ESC}
Function Keys {F1} ... {F16}
Print Screen {PRTSC}
Break {BREAK}
The full list from Microsoft can be found here
There is a small javascript utility that simulates keystrokes like this on the Windows javascript interpreter.
Just create a js file with following code:
var WshShell = WScript.CreateObject("WScript.Shell");
WshShell.SendKeys(WScript.Arguments(0));
then call it from Matlab after the necessary timeout like this:
system('c:\my\js\file\script.js {Enter}');
Can't test here now, but I think this should work...
If you need to run a console-only program in a context that permits full DOS redirection, you can create a file called, say, CR.txt containing a carriage return and use the '<' notation to pipe the value into the program.
This only works if you can provide all the keyboard input can be recorded in the file. It fails dismally if the input has to vary based on responses.
An alternative is to duplicate the input (and possibly output) stream(s) for the program and then pipe data into and out of the program. This is more robust and can permit dynamic responses to the data, but will also likely require substantial effort to implement a robot user to the application.
Rog-O-Matic is an example of a large application completely controlled by a program that monitors screen output and simulates keyboard input to play an early (1980s) ASCII graphic adventure game.
The other responses will be required for GUI-based applications.
Python package pywinauto can wait any dialog and click buttons automatically. But it's capable for native and some .NET applications only. You may have problems with pressing WPF button (maybe QT button is clickable - not checked), but in such case code like app.DialogTitle.wait('ready').set_focus(); app.DialogTitle.type_keys('{ENTER}') may help. Your case is quite simple and probably some tricks with pywinauto are enough. Is your "app with popup" 64-bit or 32-bit?
wait and wait_not functions have timeout parameter. But if you need precisely listener with potentially infinite loop awaiting popups, good direction is global Windows hooks (pyHook can listen mouse and keybd events, but cannot listen dialog opening). I'll try to find my prototype that can detect new windows. It uses UI Automation API event handlers... and... ops... it requires IronPython. I still don't know how to set UI Automation handler with COM interface from standard CPython.
EDIT (2019, January): new module win32hooks was implemented in pywinauto a while ago. Example of usage is here: examples/hook_and_listen.py.
This question already has answers here:
Stop and continue execution from debugger possible?
(6 answers)
Closed 8 years ago.
Strg+C stops and kills a Matlab script (at least sometimes). But is there a way to stop a Matlab, take a look at some variables and continue the calculation?
I am not talking about just setting a breakpoint. I want my script, let’s say run for couple hours come back to it hit some buttons that stops the calculations take a look at some variable and then continue the calculation.
I tried to find out if there is some shortcut key for this – I am quite sure there isn’t.
Now I was thinking about including an if-case that looks if a certain button was pressed by the user. If so there would be a useless k=0 line and a breakpoint on it. And if no one is pressing this button the loop would continue. But this is where my limited Matlab knowledge leaves me. I don’t know if there is a way to ask for a user-button press but don’t wait for a button press like in the function input. Also I just have a running script, I don’t have any GUI.
To drop to the command prompt you need the command keyboard and then type return when you have finished (you don't need a breakpoint). The tricky bit is how to trigger it. There a few options. The easiest is to open a figure window. The following code halts the process when any key is pressed.
keyDownListener=#(src,event) keyboard;
fig = figure;
drawnow
set(fig,'KeyPressFcn',keyDownListener)
for p=1:10000
%do some thing
end
You can modify this to test for a specific key since the keypress is contained within the event struct.
To use no figure gui at all its more of a problem. I'm not aware of a non blocking keyboard input method. A mex file the runs kbhit() in C might do it, but kbhit() is not standard C so it would only work on Windows. An easier option maybe to test for the presence of a file.
for p=1:100000
if exist(fullfile(pwd,'halt.tmp'),'file')
keyboard
end
%do something here
end
This drops to the debug console when halt.tmp is created in the current directory.
Other potential methods could involve using multiple threads to read 'input' (either the Parallel computer toolbox or undocumented Java code), or using http://psychtoolbox.org/ as mentioned by #bdecaf
I have recently started using MATLAB without GUI by starting matlab with -nodesktop option and it is considerably faster.
However presently I have no way to debug a .m script in non gui mode. I have to open the default matlab editor every time I have to debug.Has anyone figured out a way to do it?
Thanks in advance
I am using Ubuntu Linux, in case that helps.
To set breakpoints with the command line, dbstop is the tool (plus dbclear to clear breakpoints and dbstatus to list them).
There are presently 17 different forms to dbstop, which allow you to specify various combinations of:
The M-file in which to stop
Line number
Sub-function
Conditional to an arbitrary expression. For example,
dbstop in myFun.m at 224 if ~exist('x','var')
At any run-time error (dbstop if error)
At a specific error (e.g dbstop if error myFun.m:barErrorId)
At any warning (dbstop if warning) or specific warning
If NaN or Inf are encountered (dbstop if naninf)
See the documentation for dbstop for details and good examples.
Also get used to dbcont (or F5), dbstep (or F10), dbquit (Shift+F5), dbstep (also dbstep in, dbstep out), dbstack (to see where you are and how you got there). The keyboard shortcuts may be different outside of Windows.
Far less used, but still very useful are dbup and dbdown, which allow you to switch workspace context (memory stacks).
See the summary of functions and a list of examples and how-to pages in the MathWorks page on Debugging.
Related to the "db" functions is checkcode, which will check your code for possible problems before you even run it. This is a nice substitute for the red squiggly underlines that you would get in the MATLAB Editor.
Once you get a hang of dbstop and it's syntax, you won't often need to insert a keyboard into your code, but it's always an option.
Try placing the keyboard command in your code to insert a breakpoint. When the keyboard command is reached, MATLAB will drop into an interactive prompt that you can use to inspect variables. For example:
x = rand(10,10);
y = rand(10,5);
z = x * y;
keyboard; % you can interactively inspect x, y, z here
z = sort(z);
To leave keyboard mode, you can type dbquit to exit the program, or return to continue executing the program.
Another trick is to turn on dbstop if error which will automatically drop you into an interactive prompt whenever your code crashes.
You can use MATLAB -Dgdb if that helps. This sets gdb as the debugger. You will need to be familiar with gdb of course.
Once you do that, use the standard gdb commands to debug it.
EDIT
My mistake. Above won't work for M-Files. (Not having MATLAB to try things out is a pain :)
MATLAB has a pretty good set of debugging commands you can use from the commandline. If you insert keyboard commands in your MATLAB code, you can then use the commands.
You can use MATLAB's editor debug button to debug within MATLAB environment
In Octave, when typing command in the command line, sometimes I need to erase the whole line and restart a new command. In Matlab, erasing the text would be done with the ESC key. In Octave this does not work. The only way I found to discard the input text is using Ctrl-C. This works, but it is ugly, as it leaves remains on the screen.
Is there a key combination to clear the line in Octave?
to clear the command window type:
clc
There are several clearing shortcuts defined:
Meta-D: clear the next word1
Ctrl-K: clear to the end of the line
Ctrl-U: clear the whole line
Ctrl-L: clear the line and the screen
See more examples in the octave command-line-editing section of the manual.
For historical reasons Ctrl-U is usually controlled by your terminal rather than octave, although octave also supports it. You can test this with stty kill undef (restore with stty kill '^U').
1 Meta is often bound to the Win key or the Alt key. If not hit the Esc key first and then the character that needs to be "metaified".
Ctrl-A: go to beginning of line.
Ctrl-K: kill all characters starting at the cursor.
From within a MATLAB GUI application, I'm starting an external program (a console application on Windows) that takes care of reading data from a measurement system. The data is stored in several files that are processed by the MATLAB application as soon as the external program has finished. The problem is this:
The external program, when run on the command line, can be gracefully stopped by issuing a SIGINT (i.e. by pressing Ctrl + C). A signal handler traps the SIGINT and shuts down the program. Is there a way to do this from within the MATLAB GUI application, by pushing an "abort" button?
After many hours of searching I stumbled upon http://www.caam.rice.edu/~wy1/links/mex_ctrl_c_trick/ which shows how to detect SIGINT in a MEX file. Letting a MEX call the external program might work (although I'm not sure about the details yet). However, it still requires Ctrl + C to stop the program. How can I send the SIGINT via push button in my GUI?
If you start your external program in Cygwin, then Cygwin will give it a PID. Using this PID you can use Cygwin's kill command to send signals to the process. So start the program from Cygwin. In MATLAB you can use !ps (where ! means call external shell command) to get a list of Cygwin PID's and then !kill -s signal pid to send a signal to the program. To make it happen from a MATLAB GUI let the callback from some button call !kill.