title: gfortran open statement does not support blocksize?
body: <p>I am new to FORTRAN and try to re-compile some <code>.F90</code> codes in a WIN7 64-bit system with gfortan 4.5.2. The source code has been successfully compiled using LAHEY compiler, which I do not have access... My question is related to the <code>blocksize</code> option in the <code>open</code> statement, which is:</p>
  <pre><code>open (unit=RANUNT, file=trim(DAFile_Name), status='old',&amp;
      action='readwrite', recl=LENREC, access='direct',&amp;         
      form='UNformatted', blocksize=LENREC, iostat=It_is_OK) 
  </code></pre>
  <p>The error message I got is</p>
  <pre><code>    form='UNformatted', blocksize=LENREC, iostat=It_is_OK) 
                         1
  Error: Syntax error in OPEN statement at (1)
  </code></pre>
  <p>So my question: Is this <code>blocksize</code> option not supported in gfortran? What potential problems I could run into by removing it?</p>
  <p>Thanks!</p>
  <h3>Update</h3>
  <p>The program works fine in Windows XP compatibility mode. However, it complained in Windows 7 mode. The error I got in Windows 7 are:</p>
  <pre><code>Program received signal SIGSEGV: Segmentation fault - invalid memory reference.
  
  Backtrace for this error:
  #0  6f61143e
  #1  6f68ec2f
  #2  00401261
  </code></pre>