Get the status using system(command &) when program has been closed

Hello guys,

I have another question to ask for today.

I am running an .exe file that takes some time to finish and to output the status. This command runs within app designer and it makes the application unusable (I can click on the stuff but nothing will refresh during system command).

Question: How can I make the App drawnow during the ([ExeFile ' &']) or system (ExeFile)?

Since ExeFile generates another file, I wanted to check if it exists as follows:

system ([ExeFile ' &']); % 

while isfile(File_Check) == false 
drawnow
pause (0.5) 
end

But it turns out that file is generated immediately and it increases size as the ExeFile is running, so this does not seem like a good approach.

I also checked the fileattribute for the File_Check and they do not change during the execution. Edit: As stated here https://www.mathworks.com/matlabcentral/answers/296657-how-can-i-check-if-i-have-read-or-write-access-to-a-directory it turns out not to be reliable.

Are there any other ways you can think of doing this?

Edit: During the ExeFile run, I get permission denied when I want to delete the file, so, I can just try renaming the file and then rename it back when the command succeeds. But I don't see this as a great idea.

[Walter Roberson]

Are you using Windows ? The options are different for Windows.

[Mario Malic]

Yes, I am using Windows.

[Walter Roberson]

See System.Diagnostics.Process

[Mario Malic]

Will do, thanks Walter.

Answer 1

[Mario Malic]

Here's an example with simple app.

Process = System.Diagnostics.Process; 
Process.Start('notepad.exe');

% You can check if process is still running
while(Process.HasExited == false)
    % do something
end

If you are running an executable file with input arguments as linked from the answer belowhttps://www.mathworks.com/matlabcentral/answers/264364-executable-in-matlab-help#answer_206712 (It could be good if mods can accept that answer)

Exe_Process = System.Diagnostics.Process;
Exe_Process.StartInfo.Arguments = '-example arguments';
Exe_Process.StartInfo.FileName = 'C:\program.exe' % full file path
Exe_Process.Start();

% If you need to execute commands while Exe_Process is running
while Exe_Process.HasExited == false 
    % do something
    pause (0.1) % so MATLAB doesn't check if .exe has stopped silly amount of times
end

Thanks again for the hint Walter!

[Jonathan Gimeno]

Hi all,

Just wondering if there is anything similar that can be used in Linux?

I assume it would be the system command but I dont see the same functionality. Is it possible to execute something during the duration of the process while it is still running?

Thanks a lot!

[Walter Roberson]

If you system() and the command line has the & operator, then (generally) that will run in the background, and system() will immediately return.

However, there isn't really any nice way to get notified when the background process finishes.

Another approach that might be worth investigating is using a "background" pool and parfeval() a function that runs the system() command. When the system() command eventually returns, the function would exit, and you would be able to detect from the "future" returned by parfeval() that it had finished.

[Jonathan Gimeno]

Thanks for the proposed solution, unfortunately I dont have available parfeval function.

I choose to do it the hard way:

% Execute in background the system command:
command = "<command_name> & "
system(command)

% get system command pid
[status, command_pid ]= system("ps aux |grep [c]ommand_name | awk '{print $2}'");

check_pid_is_alive = strcat("ps --pid ", command_pid);
while ~(system(check_pid_is_alive))
    % do something
end

[Walter Roberson]

Ah, background thread needs r2021b