Php/docs/migration54.incompatible
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Backward Incompatible Changes
Although most existing PHP 5 code should work without changes, please take note of some backward incompatible changes:
- Safe mode is no longer supported. Any applications that rely on safe mode may need adjustment, in terms of security.
- Magic quotes has been removed. Applications relying on this feature may need to be updated, to avoid security issues. get_magic_quotes_gpc() and get_magic_quotes_runtime() now always return
FALSE
. set_magic_quotes_runtime() raises anE_CORE_ERROR
level error on trying to enable Magic quotes. - The register_globals and register_long_arrays
php.ini
directives have been removed. - The mbstring.script_encoding directive has been removed. Use zend.script_encoding instead.
- Call-time pass by reference has been removed.
- The break and continue statements no longer accept variable arguments (e.g.,
break 1 + foo() * $bar;
). Static arguments still work, such asbreak 2;
. As a side effect of this changebreak 0;
andcontinue 0;
are no longer allowed. - The default character set for htmlspecialchars(), htmlentities() and html_entity_decode() is now
UTF-8
, instead ofISO-8859-1
. Note that changing your output charset via the default_charset configuration setting does not affect htmlspecialchars/htmlentities unless you are passing "" (an empty string) as the encoding parameter to your htmlspecialchars()/htmlentities()/html_entity_decode() calls. Generally we do not recommend doing this because you should be able to change your output charset without affecting the runtime charset used by these functions. The safest approach is to explicitly set the charset on each call to htmlspecialchars(), htmlentities() and html_entity_decode(). - In the date and time extension, the timezone can no longer be set using the TZ environment variable. Instead you have to specify a timezone using the date.timezone
php.ini
option or date_default_timezone_set() function. PHP will no longer attempt to guess the timezone, and will instead fall back to "UTC" and issue aE_WARNING
. - Non-numeric string offsets - e.g.
$a['foo']
where $a is a string - now return false on isset() and true on empty(), and produce aE_WARNING
if you try to use them. Offsets of types double, bool and null produce aE_NOTICE
. Numeric strings (e.g.$a['2']
) still work as before. Note that offsets like'12.3'
and'5 foobar'
are considered non-numeric and produce aE_WARNING
, but are converted to 12 and 5 respectively, for backward compatibility reasons. Note: Following code returns different result. $str='abc';var_dump(isset($str['x'])); // false for PHP 5.4 or later, but true for 5.3 or less - Converting an array to a string will now generate an
E_NOTICE
level error, but the result of the cast will still be the string"Array"
. - Turning
NULL
,FALSE
, or an empty string into an object by adding a property will now emit anE_WARNING
level error, instead ofE_STRICT
. - Parameter names that shadow super globals now cause a fatal error. This prohibits code like
function foo($_GET, $_POST) {}
. - The Salsa10 and Salsa20 hash algorithms have been removed.
- The Tiger hash algorithm now uses big-endian byte ordering. Please follow this example to write code that is compatible with both PHP 5.3 and 5.4.
- array_combine() now returns
array()
instead ofFALSE
when two empty arrays are provided as parameters. - If you use htmlentities() with asian character sets, it works like htmlspecialchars() - this has always been the case in previous versions of PHP, but now an
E_STRICT
level error is emitted. - The third parameter of ob_start() has changed from bool
erase
to intflags
. Note that code that explicitly seterase
toFALSE
will no longer behave as expected in PHP 5.4: please follow this example to write code that is compatible with PHP 5.3 and 5.4. - stream_select() now preserves the keys of the
read
,write
andexcept
arrays.
The following keywords are now reserved, and may not be used as names by functions, classes, etc.
The following functions have been removed from PHP:
- define_syslog_variables()
- import_request_variables()
- session_is_registered(), session_register() and session_unregister().
- The aliases mysqli_bind_param(), mysqli_bind_result(), mysqli_client_encoding(), mysqli_fetch(), mysqli_param_count(), mysqli_get_metadata(), mysqli_send_long_data(), mysqli::client_encoding() and mysqli_stmt::stmt().