[php] How can I get the error message for the mail() function?

Try this. If I got any error on any file then I got error mail on my email id. Create two files index.php and checkErrorEmail.php and uploaded them to your server. Then load index.php with your browser.

Index.php

<?php
    include('checkErrorEmail.php');
    include('dereporting.php');
    $temp;
    echo 'hi '.$temp;
?>

checkErrorEmail.php

<?php
  // Destinations
  define("ADMIN_EMAIL", "[email protected]");
  //define("LOG_FILE", "/my/home/errors.log");

  // Destination types
  define("DEST_EMAIL", "1");
  //define("DEST_LOGFILE", "3");

  /* Examples */

  // Send an e-mail to the administrator
  //error_log("Fix me!", DEST_EMAIL, ADMIN_EMAIL);

  // Write the error to our log file
  //error_log("Error", DEST_LOGFILE, LOG_FILE);

  /**
    * my_error_handler($errno, $errstr, $errfile, $errline)
    *
    * Author(s): thanosb, ddonahue
    * Date: May 11, 2008
    * 
    * custom error handler
    *
    * Parameters:
    *  $errno:   Error level
    *  $errstr:  Error message
    *  $errfile: File in which the error was raised
    *  $errline: Line at which the error occurred
    */

  function my_error_handler($errno, $errstr, $errfile, $errline)
  {  
  echo "<br><br><br><br>errno ".$errno.",<br>errstr ".$errstr.",<br>errfile ".$errfile.",<br>errline ".$errline;
      if($errno)
      {
              error_log("Error: $errstr \n error on line $errline in file $errfile \n", DEST_EMAIL, ADMIN_EMAIL);
      }
    /*switch ($errno) {
      case E_USER_ERROR:
        // Send an e-mail to the administrator
        error_log("Error: $errstr \n Fatal error on line $errline in file $errfile \n", DEST_EMAIL, ADMIN_EMAIL);

        // Write the error to our log file
        //error_log("Error: $errstr \n Fatal error on line $errline in file $errfile \n", DEST_LOGFILE, LOG_FILE);
        break;

      case E_USER_WARNING:
        // Write the error to our log file
        //error_log("Warning: $errstr \n in $errfile on line $errline \n", DEST_LOGFILE, LOG_FILE);
        break;

      case E_USER_NOTICE:
        // Write the error to our log file
       // error_log("Notice: $errstr \n in $errfile on line $errline \n", DEST_LOGFILE, LOG_FILE);
        break;

      default:
        // Write the error to our log file
        //error_log("Unknown error [#$errno]: $errstr \n in $errfile on line $errline \n", DEST_LOGFILE, LOG_FILE);
        break;
    }*/

    // Don't execute PHP's internal error handler
    return TRUE;
  }


  // Use set_error_handler() to tell PHP to use our method
  $old_error_handler = set_error_handler("my_error_handler");


?>