<? ?> tags not working in php 5.3.1

问题

I just installed php 5.3.1 in my linux server and now my old work which i used to write with tags is not working at all..

Please help me out.. How can i resolve this??

回答1:

To enable short tags, enable the short_open_tag ini directive in one of the following ways (most probably not all of them will work for you):

• set the directive short_open_tag = On in your php.ini (the recommended way);
• call ini_set("short_open_tag", 1); in your code;

• add the following line to your .htaccess file:

  php_value short_open_tag 1

---

More explanation:

It's not recommend you use short tags (<? ?>). You should use the full length tags (<?php ?>). The short syntax is deprecated, and if you want to make your application portable, it's possible that short open tags are not allowed on another server and hence your application will break.

On the other hand, the echo shorthand <?= $var ?> is enabled by default since PHP 5.4 regardless of php.ini settings and will not be deprecated. You can use it instead of <?php echo $var; ?>

And for the default behaviour:

------------------------------------------------
php.ini values : short_open_tag
------------------------------------------------

PHP 4, 5_0
 * Default behaviour   : on
 * php.ini-dist        : on
 * php.ini-recommended : on

PHP 5_1, 5_2:
 * Default behaviour   : on
 * php.ini-dist        : on
 * php.ini-recommended : off

PHP 5_3:
 * Default behaviour   : on
 * php.ini-development : off
 * php.ini-production  : off

And the reason of discouraging short open tags:

This directive determines whether or not PHP will recognize code between
<? and ?> tags as PHP source which should be processed as such. It's been
recommended for several years that you not use the short tag "short cut" and
instead to use the full <?php and ?> tag combination. With the wide spread use of XML and use of these tags by other languages, the server can become easily
confused and end up parsing the wrong code in the wrong context. But because
this short cut has been a feature for such a long time, it's currently still
supported for backwards compatibility, but we recommend you don't use them.

Note also this declined RFC about short open tags for templates: http://wiki.php.net/rfc/shortags

回答2:

Looks like you got short_open_tags set to "Off" in your php.ini file. Try setting it to "On" and restart apache.

回答3:

You most likely need to turn on short tags in your PHP configuration file. Without knowing your configuration, I couldn't say where you'd find it, but you're looking for php.ini (most likely somewhere like /etc/php.ini).

In there, the setting you are after is short_open_tags. See here for all core configuration settings for PHP. However as others have mentioned, using short tags might not be the best strategy. Here is a good discussion of the reasons (for and against).

回答4:

maybe your new configuration doesnt alllow short tags. Just use <?php ?>. It is better practise anyway.

If you still want to use them you can short_open_tag directive. Also bear in mind that won't work if you have short tags disabled.

The main reason for this is so you can use inline Xml tags.

回答5:

If you use wamp or xamp, it's really easy to activate them. Just click on icon->php server->setting->allow short tag open

It's better to not use this functionality. For example xml use the same way to open header in docs.

来源：https://stackoverflow.com/questions/2476072/tags-not-working-in-php-5-3-1