title: fallocate vs posix_fallocate
body: <p>I am debating which function to use between <code>posix_fallocate</code> and <code>fallocate</code>. 
  <code>posix_fallocate</code> writes a file right away (initializes the characters to NULL). However, <code>fallocate</code> does not change the file size (when using <code>FALLOC_FL_KEEP_SIZE</code> flag). Based on my experimentation, it seems that <code>fallocate</code> does not write NULL or zero characters to the file.</p>
  
  <p>Can someone please comment based on your experience? Thanks for your time.</p>