title: PHP file_put_contents Failed to open stream, invalid argument
body: <p>Please help! I have tried figuring this out for over an hour
  What i am trying to do is to get form values via POST, and then put these into a timestamped txt file
  The error i get is: </p>
  
  <blockquote>
    <p>Warning: file_put_contents(D:\wamp\www\weboldal\hu\php\en\03-14-15-11:08:48.txt): failed to open stream: Invalid argument in D:\wamp\www\weboldal\hu\php\en\formprocessing2.php on line 18</p>
  </blockquote>
  
  <pre><code>if ($_POST["type"] == "Type1") {
      print "Type1";
      $filename = date("m-d-y-h:i:s");
      $fullfilename = "D:\\wamp\\www\\weboldal\\hu\\php\\en\\".$filename.".txt";
      print $fullfilename;
      while (file_exists($fullfilename)) {
          print "Please wait a few seconds, server is busy";
          sleep(1);
      }
      $type = $_POST["type"];
      $name = $_POST["name"];
      $email = $_POST["email"];
      $password = $_POST["password"];
      $contents = $type."r\n".$name."r\n".$email."r\n".$password;
      file_put_contents($fullfilename,$contents,LOCK_EX);
  </code></pre>
  
  <p>EDIT: The problem was that windows would not accept colons in the filename, thanks to user @Hobo Sapiens for pointing that out</p>