PHP Unconference Europe 2015

PHP tags

When PHP parses a file, it looks for opening and closing tags, which are <?php and ?> which tell PHP to start and stop interpreting the code between them. Parsing in this manner allows PHP to be embedded in all sorts of different documents, as everything outside of a pair of opening and closing tags is ignored by the PHP parser.

PHP also allows for short open tags <? and ?> (which are discouraged because they are only available if enabled with short_open_tag php.ini configuration file directive, or if PHP was configured with the --enable-short-tags option.

If a file is pure PHP code, it is preferable to omit the PHP closing tag at the end of the file. This prevents accidental whitespace or new lines being added after the PHP closing tag, which may cause unwanted effects because PHP will start output buffering when there is no intention from the programmer to send any output at that point in the script.

echo "Hello world";

// ... more code

echo "Last statement";

// the script ends here with no PHP closing tag

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User Contributed Notes 3 notes

alexander dot podgorny at somewhere dot com
21 days ago
One reason to use long tags over short is to avoid confusion with <?xml ?> notation.
billscloud dot mail at gmail dot com
14 days ago
In your paragraph you need to close your bracket.

preda dot vlad at yahoo dot com
1 year ago
So here are the valid ways to open PHP tags:

<?php ?> // standard tags
<? ?> // short tags, need short_open_tag enabled in php.ini
<% %> // asp tags, need asp_tags enabled in php.ini
<script language="php"> </script> // case insensitive

PSR-1 coding standards suggest to only use <?php ?> or <?= ?> (echo short tags) - and no other variations, and PSR-2 suggests to not close the tags in PHP only files.
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