title: Is there a csv files naming convention?
body: <p>I must download data from external csv file which is originally named 403-002-20220107.csv.</p>
  <pre><code>$csvfile = &quot;C:\wamp64\importcsv\403-002-20220701_F.csv &quot;; //Nom du fichierCSV
  if(!file_exists($csvfile)) {
       die(&quot;Fichier introuvable. Assurez-vous que vous avez précisé le bon chemin pour ce Fichier.&quot; );
  }
  </code></pre>
  <p>I got this warning message:</p>
  <blockquote>
  <p>( ! ) Warning: Octal escape sequence overflow \403 is greater than
  \377</p>
  </blockquote>
  <p>as well as a &quot;File not found&quot; message.</p>
  <p>After renaming the file as follows (name starting with a letter):</p>
  <pre><code>$csvfile = &quot;C:\wamp64\importcsv\A403-002-20220701_F.csv &quot;; //Nom du fichierCSV
  </code></pre>
  <p>it worked fine. Is this behaviour conforming with a specific file naming convention in PHP?</p>