(PHP 4, PHP 5, PHP 7)
error_reporting — Sets which PHP errors are reported
$level
  ] )
   The error_reporting() function sets the
   error_reporting
   directive at runtime.  PHP has many levels of errors, using
   this function sets that level for the duration (runtime) of
   your script. If the optional level is
   not set, error_reporting() will just return
   the current error reporting level.
  
levelThe new error_reporting level. It takes on either a bitmask, or named constants. Using named constants is strongly encouraged to ensure compatibility for future versions. As error levels are added, the range of integers increases, so older integer-based error levels will not always behave as expected.
The available error level constants and the actual meanings of these error levels are described in the predefined constants.
   Returns the old error_reporting
   level or the current level if no level parameter is
   given.
  
| Version | Description | 
|---|---|
| 5.4.0 | E_STRICTbecame part ofE_ALL. | 
| 5.3.0 | E_DEPRECATEDandE_USER_DEPRECATEDintroduced. | 
| 5.2.0 | E_RECOVERABLE_ERRORintroduced. | 
| 5.0.0 | E_STRICTintroduced (not part ofE_ALL). | 
Example #1 error_reporting() examples
<?php
// Turn off all error reporting
error_reporting(0);
// Report simple running errors
error_reporting(E_ERROR | E_WARNING | E_PARSE);
// Reporting E_NOTICE can be good too (to report uninitialized
// variables or catch variable name misspellings ...)
error_reporting(E_ERROR | E_WARNING | E_PARSE | E_NOTICE);
// Report all errors except E_NOTICE
error_reporting(E_ALL & ~E_NOTICE);
// Report all PHP errors (see changelog)
error_reporting(E_ALL);
// Report all PHP errors
error_reporting(-1);
// Same as error_reporting(E_ALL);
ini_set('error_reporting', E_ALL);
?>
    Most of E_STRICT errors are evaluated at the
    compile time thus such errors are not reported in the file where
    error_reporting is enhanced
    to include E_STRICT errors (and vice versa).
   
    Passing in the value -1 will show every possible error,
    even when new levels and constants are added in future PHP versions. The
    E_ALL constant also behaves this way as of PHP 5.4.