MATLAB: Does externally called .exe using the ‘system’ command freeze on the third call

external programsystem command

I have a Matlab script (R2011b) that calls and external compiled C# program. The C# program opens up a remote application, loads some data, and then saves that data. When I run the C# program from the cmd line it runs just fine and I can run it over and over again. However, when I run the program through Matlab withe the 'system' command it runs fine the first and second time but on a third time it hangs when it tries to save the data. Any suggestions on what might be going on here? I've tried calling the program through a batch file also and also tried compiling the Matlab code but the results were the same. Thanks in advanced for any suggestions.

Best Answer

While I don't know why Matlab is causing this issue when using the 'system' command, I did stumble across a working solution. Instead of using the 'system' command to call the .exe I instead us the Java runtime to make the call. Sample code below that seems to work (where 'executable' is the variable that contains the .exe string):

rt=java.lang.Runtime.getRuntime(); pr = rt.exec(['cmd /c start /wait ' executable]); pr.waitFor();

Related Solutions

MATLAB: Multithreading does not work for external programs called by the ‘system’ command

I have seen this before. I think this is how we resolved it.

Basically, MATLAB and Windows may use different environment variables.

If your application is using the OMP_NUM_THREADS environment variable, you can set this directly in MATLAB.

setenv('OMP_NUM_THREADS',numOfThreads);

More info here

MATLAB: How to call Cygwin command pipeline with the MATLAB ‘system’ function

Disclaimer: Cygwin is a Linux emulator in Windows. Cygwin is not in the supported platform list. This article is meant as a self-help resource for customers with the similar issues.

In this issue, there are several things to understand to find the right solution:

1. The 'system' function of MATLAB only passes the command to the operating system (OS) and has no control over how the passed command is executed.

2. Installing Cygwin does not grant the OS the knowledge to the counterpart executables of the Linux commands. These executables reside under the 'bin' sub-directory under the Cygwin installation directory.

3. Forward slash ('\') works for Windows shell but not for the Cygwin shell.

4. Two single quotes ('''') do not act as a double quote ('"') in the Windows shell.

5. The semicolon (';') works as a pipeline in Cygwin (or real Linux) but not in a Windows shell.

With the above understanding, the code in the question should be revised as below. The primary change is to include the full paths to each invoked Cygwin commands.

>> clear;
>> cygwinPath = 'C:\cygwin\bin'; % the value depends on the actual installation of Cygwin
>> cw_gzip = fullfile(cygwinPath, 'gzip');
>> cw_sed = fullfile(cygwinPath, 'sed');
>> cw_split = fullfile(cygwinPath, 'split');
>> cw_date = fullfile(cygwinPath, 'date');
>> inputfname = 'input.gz';
>> nlines = 5;
>> outprefix = ''
>> system(cw_date); % separate call to 'date' without using ';' for pipeline separation, which is not supported in Windows
>> pipeline = sprintf(...
>>    ['%s -dc %s | '...
>>     '%s -n \"2p;4~2p\" | ' ...
>>     '%s -a 3 -d -l %d --numeric-suffix=1 --additional-suffix=%s '...
>>     '--filter=\"%s > $FILE.gz\" - %s/file'], ...
>>     cw_gzip, name2, ...
>>     cw_sed, ...
>>     cw_split, nlines, '_r2_callqual.txt', ...
>>     strrep(cw_gzip,'\','/'),...
>>     outdir);
>> system(pipeline);
>> system(cw_date);

Best Answer

Related Solutions

MATLAB: Multithreading does not work for external programs called by the ‘system’ command

MATLAB: How to call Cygwin command pipeline with the MATLAB ‘system’ function

Related Question