PHP 5.3.0 introduces two new error levels: E_DEPRECATED and E_USER_DEPRECATED. The E_DEPRECATED error level is used to indicate that a function or feature has been deprecated. The E_USER_DEPRECATED level is intended for indicating deprecated features in user code, similarly to the E_USER_ERROR and E_USER_WARNING levels.

The following is a list of deprecated INI directives. Use of any of these INI directives will cause an E_DEPRECATEDerror to be thrown at startup.

■define_syslog_variables
■register_globals 【默认应该是off，为了安全性起见】
■register_long_arrays 【用短的$_GET等，而不是$HTTP_GET_VARS】
■safe_mode
■magic_quotes_gpc 【默认应该是Off，为了避免移植性的问题，另外数据库的安全性问题，应该交给应用层来做】
■magic_quotes_runtime
■magic_quotes_sybase

■Comments starting with '#' are now deprecated in .INI files.【那就使用;来注释吧 】

Deprecated functions:
■call_user_method() (use call_user_func() instead)
■call_user_method_array() (use call_user_func_array() instead)
■define_syslog_variables()
■dl()
■ereg() (use preg_match() instead)
■ereg_replace() (use preg_replace() instead)
■eregi() (use preg_match() with the 'i' modifier instead)
■eregi_replace() (use preg_replace() with the 'i' modifier instead)
■set_magic_quotes_runtime() and its alias, magic_quotes_runtime()
■session_register() (use the $_SESSION superglobal instead)
■session_unregister() (use the $_SESSION superglobal instead)
■session_is_registered() (use the $_SESSION superglobal instead)
■set_socket_blocking() (use stream_set_blocking() instead)
■split() (use preg_split() instead)
■spliti() (use preg_split() with the 'i' modifier instead)
■sql_regcase()
■mysql_db_query() (use mysql_select_db() and mysql_query() instead)
■mysql_escape_string() (use mysql_real_escape_string() instead)
■Passing locale category names as strings is now deprecated. Use the LC_* family of constants instead.

■The is_dst parameter to mktime(). Use the new timezone handling functions instead.

Deprecated features:
■Assigning the return value of new by reference is now deprecated.
■Call-time pass-by-reference is now deprecated.
■The use of {} to access string offsets is deprecated. Use [] instead.
ereg开头的函数，已经不建议使用了。