error log

error_log.php

<?php
error_log('A connection to the database could not be opened.', 1, 'errors@php.net'); //send error to email

error_log('A connection to the database could not be opened.', 3, '/var/log/php_errors.log'); //log into a file 
?>

log_rolling_error_handler.php

<?php
//shows an example of an error handler that writes logs into a file and rotates the logfile when it gets above 1 KB.

  function log_roller($error, $errorString)
  {
  $file = '/var/log/php_errors.log';
  if(filesize($file) > 1024) {
  rename($file, $file . (string) time());
  clearstatcache();
  }
  }
  error_log($errorString, 3, $file);
  set_error_handler('log_roller');
  for($i = 0; $i < 5000; $i++) {
  trigger_error(time() . ": Just an error, ma'am.\n");
  }
  restore_error_handler();
?>