Check for PREG errors after preg_* function call

RegExp_error_check.php

 switch( preg_last_error() ){
                  case PREG_NO_ERROR :
                      $preg_error = 'No error';
                      break;
                  case PREG_INTERNAL_ERROR :
                      $preg_error = 'An internal PCRE error';
                      break;
                  case PREG_BACKTRACK_LIMIT_ERROR :
                      $preg_error = 'Backtrack limit was exhausted';
                      break;
                  case PREG_RECURSION_LIMIT_ERROR :
                      $preg_error = 'Recursion limit was exhausted';
                      break;
                  case PREG_BAD_UTF8_ERROR :
                      $preg_error = 'Malformed UTF-8 data';
                      break;
                  case PREG_BAD_UTF8_OFFSET_ERROR :
                      $preg_error = 'Offset didn\'t correspond to the begin of a valid UTF-8 code point';
                      break;
        
              }