file SEEK behavior changed

[Daniel J Sebald]

I came across a change in behavior for the file I/O between 2.1.46 and 
2.1.57.  It has to do with the "fread" reading past the end of the file. 
The following code used to work fine in 2.1.46.  It is part of an 
application that will read in LENGTH samples of data and display the 
data; it steps through the data upon the user hitting the proper key 
stroke.  When it gets to the end of the file and runs out of data, this 
chunk of code is supposed to realign with the end of the file.

     [x_c,N_x_c] = fread(ifid,LENGTH,'int16');
     %# Position to last block in file if read past end.
     if (N_x_c < LENGTH)
         if ((ipos + N_x_c) < LENGTH)
            LENGTH = ipos + N_x_c;
            OVERLAP = floor(LENGTH/5);
            f_res = min(floor(LENGTH/40)*2, MAX_FFT_SIZE);
         end
*          cstatus = fseek(ifid, -2*LENGTH, SEEK_END);
         ipos = ftell(ifid)/2;
         [x_c,N_x_c] = fread(ifid,LENGTH,'int16');
         if (create_pdf_file)
             %# Make this the last page if creating a PDF file.
             finished = 1;
         end
     end

However, in 2.1.57 this code fails to realign to the end of the file. 
In particular, the line I marked above with a star (*) keeps coming 
back with a -1 instead of a 0.  My fix has been to close the file and 
reopen it right before the * line of code.  This fixes the problem so 
that it now behaves like it did in 2.1.46.

Dan