I was looking through an error message that MATLAB gave me when I saw the command opentoline. After opening its help doc:
opentoline Open to specified line in function file in Editor.
Doesn't this serve the same purpose as goto as it can take you to the specific line number of any program?
opentoline will open the file in Matlab's editor. That's handy if a routine indicates a problem in a specific file/line. Then it can jump (or offer a link) to this location and the user sees the file/line.
goto is only for execution, it jumps to the position on execution and will continue executing from the goto target. The editor is not involved in this case. BTW, there is no built-in goto statement in Matlab, but functions called goto from third parties. I wouldn't use them anyway.
Related
In Matlab, is it possible to set a data breakpoint on a specific variable as it is done in Visual Studio? I could not find anything online and in the manual, can really such a important feature be missing?
It does its called conditional breakpoints.
You can set them at the command line but its a lot easier to put them in interactively via the editor (right click on "-" next line number and select "Set Conditional Breakpoint"
Commandline:
dbstop in FUNCTION at LINENO if 'EXPRESSION'
I have an executable created with mcc. The .m file has a simple function that reads and plots values. After I run it from DOS, it freeze without returning execution to DOS. 2 questions:
1) How can i return execution to dos? I tried "return" and "exit" commands but didnt help
2) How to close the dos windows? is the only way to use a batch file or can I do it with a command in the .m file?
thanks
A.
There are 2 scenarii:
If your run your matlab executable from a DOS window, the DOS window will not get control back until the program terminates. If the program generate matlab figures (plot, surf, etc...), the program will not return to the console until all of the figures are closed.
You may think it is a waste for a simple plot, but after all your figure could be a evolved gui with a lot of code to execute. Or even a simple figure with a closeRequestFcn. So in Matlab terms, your program may still have instructions to execute as long as a figure is opened, so it will not return until it sure there is nothing more to do.
If you simply double clicked on your executable, the DOS looking console which open with your program will have the same behaviour. It will not disappear until the program returns (so until all your figures are closed if relevant).
I am not sure about linux, versions, but if you are running on windows, there is a way to suppress the DOS looking console for your graphic applications. Look at the -e switch in the mcc options.
This switch will compile your program in a way that no DOS console is opened when you double click on your executable.
So to summarize, I would recommend:
If your program is a 'command line' type (a function that takes input from the console and return values to the same). => Compile with normal options, and execute it from a DOS window (you do not want the window to disapear as soon as the program terminates.)
If your program is a gui or even simple plotting functions, with no need for console interactions, then compile with the -e switch and execute it by double clicking the .exe file.
note that in case you use the -e switch, it is recommended to direct potential output to a logfile. Look at the mcc documentation for more info.
edit
If you really need the DOS console and some graphic output, run your program form the command window with the following syntax:
start /b YourProgram
This will start the program in "background mode" (use YourProgram & in Linux terminal). You will be able to do anything in this console window, and you will also see the output from your matlab executable.
It can be confusing because the output from your program will be added to the simple dos prompt and you may think you do not have the control but if you type any command it will work. You can even start many program this way and retain control in your console, but all the output will arrive in the same window and they may be difficult to differentiate.
I need to know how to keep a window open so I can see the output of the screen when I run the program. It flashes before I can see the program's output. Thanks.
program-id. Experiment as "Experiment".
environment division.
configuration section.
Source-Computer. IBM-PC.
Object-Computer. IBM-PC.
special-names.
console is crt.
data division.
working-storage section.
procedure division.
Experiment-Start.
Display "Hello World".
end program Experiment.
I think you are describing normal behaviour.
If the Operating System has to open a window to run a program, then the Operating System will close that window when the program ends.
If you open the window, to get a DOS-prompt, and run the program, you will get different behaviour.
A little trick for testing is to put DISPLAY/ACCEPT statement immediate before the program ends:
In the WORKING-STORAGE SECTION
01 some-rubbish PIC X.
In the PROCEDURE DIVISION.
DISLAY "The Program is ending. Press Enter to allow it to finish."
ACCEPT some-rubbish FROM CONSOLE
There may well be something available in Eclipse, as it is a common development requirement, but until you find that, this should get you going.
This question already has answers here:
Stop and continue execution from debugger possible?
(6 answers)
Closed 6 years ago.
In MATLAB, I'm running some code which takes a while to run. I'd like to pause the code to check on some variable values. Is there a way I can do this without having to re-run the code from the beginning? I don't want to terminate the program; just pause it.
You can halt execution and give a command prompt in two ways of which I am aware:
Putting keyboard in your code where you want to stop.
Setting a breakpoint.
You can resume and stop execution with dbcont and dbquit, respectively. To step forward, use dbstep. dbstack lets you see where you are. There are many more commands. The help page for any of these will give you other suggestions.
As Dennis Jaheruddin has pointed out, dbstop also has several useful features worth trying. In particular is the ability to set conditional and global (any line meeting a criterion) breakpoints via the dbstop if syntax. For example, dbstop if error will break to a debugging command prompt on any error. One suggestion he made, which I now do, is to put dbstop if error into startup.m so that this behavior will be default when you start MATLAB. You may need to create this file in a userpath folder; edit(fullfile(regexp(userpath,'^[^;]*','match','once'),'startup.m')).
One way to achieve what you're looking for would be to use code sections (also known as code cells), where you divide your code into sections divided by lines with two percent signs (%%).
Then, in the editor, you can press ctrl+enter to execute the current code section, and ctrl+up/down to navigate between sections.
Well there is the pause command, but then you cannot check for the variable contents in the workspace because the program is running.
What you probably want is to set a breakpoint (See the Debug menu / key F12).
At a breakpoint matlab pauses the program and enters debugging mode in which you can see and edit the variables. Once finished, you can resume the program where it was paused.
I'm not sure about Windows users but if you're running Linux you can start Matlab in a terminal using
matlab -nodesktop
then once Matlab has started, cd to your project directory and start your Matlab script. Now whenever you want to pause execution you can use ctrl-Z. Then to resume type fg. I hope this helps.
I want to force the current execution line to a specific line in the same function, possibly skipping intermediate lines. All my old school debuggers had this feature, but I can't find it in eclipse. Is there a way to do it without changing code?
The first two answers seem to miss the topic, unless it is me not understanding the question.
My understanding, a feature I searched myself, is that you want to skip a number of lines (when stepping in code) and set the program counter (to take assembly vocabulary) to the given line. It might be interesting to skip some costly object creation, see some error situations, etc. I used to do that in Visual Studio (C or C++ code).
I haven't found that in Eclipse, nor in NetBean. It might be a limitation of JVM, or an enforcement of some policy...
The Run to line command execute, of course, all lines between the current execution position and the designated one.
I too have long sought this feature, and "Run to line" is not the same thing.
This may well be a limitation of the JVM. Java does not implement goto, though it does have jump statements, like break and continue. Those are at the block level however. If this is a JVM limitation, my guess is that it is more likely due to the security architecture. Tight control of the program counter is debilitating for interlopers, like viruses -- and sadly debuggers.
I think that is not possible in Java. The only feature that allows you to "step back" is using "drop to frame", which takes you back to the first instruction of the current frame. At least I haven't seen any debugger with this specific functionality, but I haven't been able to find on the net why is it so...
I know the debugger in Visual C allows to change to pointer. I will keep on searching, maybe at least we will know why is like this, but it seems to be some kind of design limitation.
Feature request saying it is not possible
In https://bugs.eclipse.org/bugs/show_bug.cgi?id=287795 (credits to Amitd) Darin Wright says it is a limitation of the underlying Java debugger:
Currently, this is not possible with the Java debugger as the native debug interface does not provide the ability to move/set the program counter arbitrarily.
C / C++
CDT supports it however (tested on Neon, Ubuntu 14.04). Right click on the line you want to go to, and select either:
"Move to line": jump to line and break there
"Resume at line": jump to line and continue execution from there
This also serves as further evidence that there is an underlying Java limitation, as Java tends to be more feature rich in Eclipse, and those menu entries are not present in Java next to "Run to line" (which does not skip execution of lines).
This test program prints 0 if you jump the line i = 1:
#include <stdio.h>
int main(void) {
int i;
i = 0; /* Break here. */
i = 1;
printf("%d\n", i); /* Jump to here. */
}
"Run to line" appears to need the program to be running and in a paused state to use. The other option is to set a breakpoint for that line when running in debug-mode.
Double-click far-left vertical bar in the source pane on the same line to add a breakpoint; or,
Select the line and go to Run > Toggle Breakpoint.
At least, this is in Eclipse 3.3.2.