how to open multiple files and write to those open files at the same time in a loop

Hi I try to write three different two dimensional table of which the data is calculated in a single loop to a file dedicated to each table; hence three different files.

my code starts like this:

      fid1 = fopen(filename1, 'w');
      if fid1 == -1, error('Cannot open file'); end

      fid2 = fopen(filename2, 'w');
      if fid2 == -1, error('Cannot open file'); end

      fid3 = fopen(filename3, 'w');
      if fid3 == -1, error('Cannot open file'); end

Then i want to write somethings to the files like this :

%for loop where the essence looks like this: 
for 
   [parameter_1,parameter_2,parameter_3] = calculations()
   fprintf(fid1,'\t%g',parameter_1);
   fprintf(fid2,'\t%g',parameter_2);
   fprintf(fid3,'\t%g',parameter_3);        
end

I get the error 'cannot open file' as soon as matlab tries open the second file (filename2). When i comment out the second and third line i get the same error for the third file (filename3); hence could it be that Matlab cannot open several files simultaniously to write to?

If this correct,is there an alternative way to circumvent this problem?

thanks!

[dpb]

Not a limitation in Matlab, no.

Most likely either filename[2|3] is already open for another process during your debugging or similar problem.

Use the alternate second return to fopen to get more info on why the operation is failing...

[fid2,msg] = fopen(filename2, 'w');
msg

And, of course, make sure the path you're trying to write to is one for which you have write privilege and so on...

[Simon]

In addition: Use

fclose('all')

to close all open files