Displaying progress from a file compiled to MEX with MATLAB Coder.

I have a slow running .m file that I am compiling to MEX via MATLAB Coder.

I would like to display the loop counter in the code's main loop.

However, with an fprintf, nothing is getting printed until the function exits.

I have tried the following, but even this does not fix the problem completely:

 if ~coder.target( 'MATLAB' )
     coder.cinclude( 'fflushStdOut.h' );
 end

 ... 

 fprintf( '%d\n', NSample );
 if ~coder.target( 'MATLAB' )
     coder.ceval( 'fflushStdOut', int32( 0 ) );
 end
 drawnow update;

Where fflushStdOut.h contains:

 #ifndef FFLUSH_STD_OUT_H
 #define FFLUSH_STD_OUT_H

 #define fflushStdOut( x ) fflush( stdout );

 #endif

Even with this, the function is still not displaying anything until 1800+ iterations have past, which takes a good 30 minutes.

Any ideas?

Answer 1

[Denis Gurchenkov]

A combination of 'drawnow' and 'mexPrintf' seem to work:

function test1
  coder.extrinsic('drawnow');
  for i = 1:1000
      coder.ceval('mexPrintf', ['hello' 10 0]);
      drawnow();
      coder.ceval('Sleep', int32(100));

    end

end

codegen test1 -config:mex
test1_mex

Prints 'hello' every 0.1 seconds

See also how to use mexPrintf in mex