[TYPO3-dev] version number of extension

[Andreas Otto]

Hi Franz,

Franz Holzinger wrote:
> Or should a function be
> written to fetch the version number from ext_emconf.php as a number? A
> number value will be needed for easier comparison.

Using the version number from ext_emconf.php is a good start. To compare
this version number with "some other" version number can be done using the
PHP function version_compare().

version_compare
(PHP 4 >= 4.1.0, PHP 5)
version_compare --  Compares two "PHP-standardized" version number strings 

Description
mixed version_compare ( string version1, string version2 [, string
operator] )

version_compare() compares two "PHP-standardized" version number strings. 

This is useful if you would like to write programs working only on some
versions of PHP. 

version_compare() returns -1 if the first version is lower than the second,
0 if they are equal, and +1 if the second is lower. 

The function first replaces _, - and + with a dot . in the version strings
and also inserts dots . before and after any non number so that for example
'4.3.2RC1' becomes '4.3.2.RC.1'. Then it splits the results like if you
were using explode('.', $ver). Then it compares the parts starting from
left to right. If a part contains special version strings these are handled
in the following order: dev < alpha = a < beta = b < RC < pl. This way not
only versions with different levels like '4.1' and '4.1.2' can be compared
but also any PHP specific version containing development state. 

If you specify the third optional operator argument, you can test for a
particular relationship. The possible operators are: <, lt, <=, le, >, gt,
>=, ge, ==, =, eq, !=, <>, ne respectively. Using this argument, the
function will return TRUE if the relationship is the one specified by the
operator, FALSE otherwise. 

Note:  PHP_VERSION constant holds current PHP version. 

Example 1. version_compare() example
 <?php
 // prints -1
 echo version_compare("4.0.4", "4.0.6");
 
 // these all print 1
 echo version_compare("4.0.4", "4.0.6", "<");
 echo version_compare("4.0.6", "4.0.6", "eq");
 ?>


Cheers,
Andreas

-- 
Andreas Otto

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