title: Find a char or substring with specifying start pos
body: <p>I couldn't find a function which would let me specify the start pos for beginning a char or substring search.</p>
  
  <p>I have, for example:</p>
  
  <pre><code>char *c = "S1S2*S3*S4";
  </code></pre>
  
  <p>I'd like search for '<code>S3</code>' by searching the first '<code>*</code>' asterisk and then the second asterisk following it and finally getting the substring '<code>S3</code>' enclosed by those asterisks. </p>