升级到5.3注意的问题:

增加了Deprecated 错误级别 http://php.net/manual/en/migration53.deprecated.php

Deprecated features in PHP 5.3.x

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_DEPRECATED error to be thrown at startup.

• define_syslog_variables
• register_globals
• register_long_arrays
• safe_mode
• magic_quotes_gpc
• magic_quotes_runtime
• magic_quotes_sybase
• Comments starting with '#' are now deprecated in .INI files.

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.