If I run the following foo.m file with run('foo.m'):
try
disp(r3)
catch ME
disp('Exception handling.')
end
I correctly get:
Exception handling.
However if I replace disp(r3) by disp('foo' 1) then I get:
Error: File: C:\Users\Pedro\Desktop\foo.m Line: 23 Column: 16
Unexpected MATLAB expression.
Error in run (line 96)
evalin('caller', [script ';']);
Why am I not catching this error with catch ME? How can I catch it?
Having a syntax error in your file, not a single line of code is broken, the full file is broken because it can not be parsed. Matlab will refuse to "understand" any code you write in your foo.m, including your try/catch. You have to write your try/catch into another function which calls the foo.m
try
foo()
catch ME
disp('Exception handling.')
end
As the matlab interpreter will highlight all syntax errors to you without running the code, you typically don't need to check for syntax errors on runtime.
Related
I am trying out a project https://github.com/janstenum/GaitAnalysis-PoseEstimation and when I run the command correctLegID_openpose.m as said in the documentation, I get this error
Not enough input arguments.
Error in correctLegID_openpose (line 3)
file = sprintf('%s%s',output_name,'_openpose.mat');
Error in run (line 91)
evalin('caller', strcat(script, ';'));
I tried running the command normally by using
run("correctLegID_openpose.m")
run() is for scripts, not for functions that take arguments. If correctLegID_openpose.m is on your Matlab search path, you can just call it directly and supply the missing input argument:
output_name = 'filename';
correctLegID_openpose(output_name)
Following this manual page 195, I run the f = mirfeatures(a), where a is a miraudio('mysong.wav') object. Then I want to get the results stored in f. However, I get the following error after this command: f.dynamics.rms{1}
Brace indexing is not supported for variables of this type.
and the following warning after this command: f.dynamics.rms
Warning: Error updating Text.
String scalar or character vector must have valid interpreter syntax:
RMS energy, E:\Video-Project\Watches\audio_320k_44100_1122002.wav
> In defaulterrorcallback (line 12)
In mirscalar/display_figure (line 390)
In mirscalar/display (line 10)
I need to mention that when I run mirrms(a). I get no warning. The mentioned commands are on the manual page 195.
Also. f.dynamics.rms generates a figure.
Here is the code and the audio file:
a = miraudio('audio_320k_44100_1122002.wav');
f = mirfeatures(a);
f.dynamics.rms;
f.dynamics.rms{1};
Is there a simple way to configure a MATLAB script so that it exits upon encountering an unhandled exception (as opposed to reverting to the REPL)?
The reason for this is that when executing many runs of a script in (unsupervised) batch mode, any script that fails should exit immediately, and not hang indifinitely at (unattended) interactive prompt.
IMPORTANT CLARIFICATION: this script is meant to be executed from the Unix command line, not from the MATLAB interactive prompt. More specifically, the script is to be invoked with
matlab -nodesktop -nosplash -nojvm -r myscript.m
The script should always terminate MATLAB after it has executed all its code, and return a status code reflecting its success (0) or failure (some non-zero integer).
I'm looking for a global setting (or a command-line flag) that can be put into effect without affecting the rest of the code.
IOW, I'm looking for something analogous to the -e flag available in some Unix shells (e.g. bash, zsh), which has the effect of aborting a script immediately whenever the return status of a statement is non-zero (meaning that the statement failed).
I know that I can wrap the entire body of a script with a try-catch, like this (for example):
try
exit_code = 0;
%
% BODY OF SCRIPT
%
catch exc
fprintf(2, 'CAUGHT EXCEPTION:\n');
fprintf(2, '%s(%d): %s\n', exc.stack.file, exc.stack.line, exc.message);
exit_code = 1;
end
exit(exit_code);
...but, as I said above, I'm looking for something simple, with no, or at most minimal, impact on the code.
The default behavior when an unhandled exception occurs is that information about the error will be printed to the command window and control will return to the command window. You should not be getting an interactive prompt from the error unless you've explicitly enabled it with dbstop if error or there is a try/catch with a keyboard command in the catch block. To just get a plain error rather than an interactive prompt you can use dbclear if error to disable this behavior. I would check your startup files to make sure that you don't have dbstop if error in there.
A try/catch pair is really the only way that this can be done. What you can do is wrap your calls to your script with another file and put the call to your script within a try/catch block. This has the added benefit that you don't have to modify the script itself, just the "runner".
Also you won't want to use exit as that completely exits MATLAB.
your_script.m
disp('Doing my thing')
error('Throwing an error!')
calling_script.m
for k = 1:100
try
% Call your other script and hope for no errors!
your_script
catch ME
% Print information about the error and continue
fprintf(2, 'CAUGHT EXCEPTION:\n');
fprintf(2, '%s(%d): %s\n', ME.stack.file, ME.stack.line, ME.message);
end
end
Update
Based upon the clarification that you've provided that you want to run this from the Unix command line, you'll still want to use something similar with a try/catch statement combined with exit. Again, you could do this in an external file as shown above
calling_script.m
code = 0;
try
your_script
catch ME
fprintf(2, 'CAUGHT EXCEPTION:\n');
fprintf(2, '%s(%d): %s\n', ME.stack.file, ME.stack.line, ME.message);
code = 1;
end
exit(code)
I have a Matlab file with multiple functions defined. When calling the file, I get the following error: "Error: File: kmeans.m Line: 20 Column: 1\n Function definition is misplaced or improperly nested."
How can I get rid of the error?
Make sure every function has a matching end.
I have a Matlab function which runs into few thousands of lines of code. Under certain condition, it is breaking. I can as well, debug the code and run step-by-step.
So, I have try, catch block in Matlab to handle the error. In addition to this, is it possible to capture, the line number of the code as well.
For Example :
try
Error here <-----
catch err
disp(['Error occured on line No ' num2str(lineNo])
end
Any idea, how it can be implemented ?
Try this. This will print out the line numbers along with the full stack.
try
%some code;
catch exc
getReport(exc, 'extended')
end
You may also consider using
>> dbstop if error
before running the code: this way when an error occurs, Matlab creates a debug breakpoint and allow you to debug at the error.
You can try in this way:
try
Error here <--------------
catch err
disp([err.identifier]);
disp([err.message]);
for e=1:length(err.stack)
disp(['Error in ' err.stack(e).file ' at line ' num2str(err.stack(e).line)]);
end
end
To print the line number you can use this command:
printf(['Line number ' num2str(dbstack.line) '\n'])