(PHP 4 >= 4.1.0, PHP 5, PHP 7)
version_compare — Compares two "PHP-standardized" version number strings
version_compare() compares two "PHP-standardized" version number strings.
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 compares the parts starting from left to right. If a part contains special version strings these are handled in the following order: any string not found in this list < dev < alpha = a < beta = b < RC = rc < # < pl = p. 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.
version1First version number.
version2Second version number.
operator
If the third optional operator argument is
specified, test for a particular relationship. The possible operators
are: <, lt,
<=, le, >,
gt, >=, ge,
==, =, eq,
!=, <>, ne
respectively.
This parameter is case-sensitive, values should be lowercase.
By default, 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.
When using the optional operator argument, the
function will return TRUE if the relationship is the one specified
by the operator, FALSE otherwise.
The examples below use the PHP_VERSION constant,
because it contains the value of the PHP version that is executing
the code.
Example #1 version_compare() examples
<?php
if (version_compare(PHP_VERSION, '6.0.0') >= 0) {
echo 'I am at least PHP version 6.0.0, my version: ' . PHP_VERSION . "\n";
}
if (version_compare(PHP_VERSION, '5.3.0') >= 0) {
echo 'I am at least PHP version 5.3.0, my version: ' . PHP_VERSION . "\n";
}
if (version_compare(PHP_VERSION, '5.0.0', '>=')) {
echo 'I am using PHP 5, my version: ' . PHP_VERSION . "\n";
}
if (version_compare(PHP_VERSION, '5.0.0', '<')) {
echo 'I am using PHP 4, my version: ' . PHP_VERSION . "\n";
}
?>
Note:
The
PHP_VERSIONconstant holds current PHP version.
Note:
Note that pre-release versions, such as 5.3.0-dev, are considered lower than their final release counterparts (like 5.3.0).
Note:
Special version strings such as alpha and beta are case sensitive. Version strings from arbitrary sources that do not adhere to the PHP standard may need to be lowercased via strtolower() before calling version_compare().
[editors note]
snipbit fixed after comment from Matt Mullenweg
--jm
[/editors note]
so in a nutshell... I believe it works best like this:
<?php
if (version_compare(phpversion(), "4.3.0", ">=")) {
// you're on 4.3.0 or later
} else {
// you're not
}
?>
What PHP.net page is any good without a classy userland implementation of a function already provided by PHP? Generally, there are pseudo-benchmarks and reasons why you'd want to use their "far superior" implementations.
Since exit is a difficult construct to implement, and exit cannot be called using variable functions, this function is <blink>BETTER</blink>.
While you cannot use this code without parentheses, you'll find that this exit function improves your site's performance with at least 25 teraflops of flux computing power!
I used to be a fan of die;, I even tried to use exit;, but now; I'm a true-blue userland_exit() fan, now with 20% more.*
*-Over the top competing brand.
<?php
function userland_exit($death_call=null)
{
if (version_compare(PHP_VERSION,'4.2.0','<'))
echo $death_call;
elseif (!is_int($death_call))
echo $death_call;
error_reporting(0);
trigger_error(null,E_USER_ERROR);
}
userland_exit("I'm dead");
?>
Something that may trip some folks up, but is useful to mention is that the following version comparison does not work quite as I expected:
version_compare('1.0.1', '1.0pl1', '>')
However, its quite easy to get working:
version_compare('1.0.1', '1.0.0pl1', '>')
Since this function considers 1 < 1.0 < 1.0.0, others might find this function useful (which considers 1 == 1.0):
<?php
//Compare two sets of versions, where major/minor/etc. releases are separated by dots.
//Returns 0 if both are equal, 1 if A > B, and -1 if B < A.
function version_compare2($a, $b)
{
$a = explode(".", rtrim($a, ".0")); //Split version into pieces and remove trailing .0
$b = explode(".", rtrim($b, ".0")); //Split version into pieces and remove trailing .0
foreach ($a as $depth => $aVal)
{ //Iterate over each piece of A
if (isset($b[$depth]))
{ //If B matches A to this depth, compare the values
if ($aVal > $b[$depth]) return 1; //Return A > B
else if ($aVal < $b[$depth]) return -1; //Return B > A
//An equal result is inconclusive at this point
}
else
{ //If B does not match A to this depth, then A comes after B in sort order
return 1; //so return A > B
}
}
//At this point, we know that to the depth that A and B extend to, they are equivalent.
//Either the loop ended because A is shorter than B, or both are equal.
return (count($a) < count($b)) ? -1 : 0;
}
?>
If you're careful, this function actualy works quite nicely for comparing version numbers from programs other than PHP itself. I've used it to compare MySQL version numbers. The only issue is that version_compare doesn't recognize the 'gamma' addition that mysql uses as being later than 'alpha' or 'beta', because the latter two are treated specially. If you keep this in mind though, you should have no problems.
This little script can perhaps help you understand version comparison a little better - the output is displayed in the comment at the top. Tweak the list of versions if you need more examples...
<?php
# 1 lt 1.0
# 1.0 lt 1.01
# 1.01 eq 1.1
# 1.1 lt 1.10
# 1.10 gt 1.10b
# 1.10b lt 1.10.0
header('Content-type: text/plain');
$versions = array(
'1',
'1.0',
'1.01',
'1.1',
'1.10',
'1.10b',
'1.10.0',
);
$comps = array(
-1 => 'lt',
0 => 'eq',
1 => 'gt'
);
foreach ($versions as $version) {
if (isset($last)) {
$comp = version_compare($last, $version);
echo str_pad($last,8,' ',STR_PAD_LEFT) . " {$comps[$comp]} {$version}\n";
}
$last = $version;
}
?>
I know this is somewhat incomplete, but it did a fair enough job for what I needed. I was writing some code that needed done immediately on a server that was to be upgraded some time in the future. Here is a quick replacement for version_compare (without the use of the operator argument). Feel free to add to this / complete it.
<?php
function version_compare2($version1, $version2)
{
$v1 = explode('.',$version1);
$v2 = explode('.',$version2);
if ($v1[0] > $v2[0])
$ret = 1;
else if ($v1[0] < $v2[0])
$ret = -1;
else // Major ver are =
{
if ($v1[1] > $v2[1])
$ret = 1;
else if ($v1[1] < $v2[1])
$ret = -1;
else // Minor ver are =
{
if ($v1[2] > $v2[2])
$ret = 1;
else if ($v1[2] < $v2[2])
$ret = -1;
else
$ret = 0;
}
}
return $ret;
}
?>
Actually, it works to any degree:
<?php
version_compare('1.2.3.4RC7.7', '1.2.3.4RC7.8')
version_compare('8.2.50.4', '8.2.52.6')
?>
will both give -1 (ie the left is lower than the right).
This function is also usefull when working with multiple installations.
As php5.3+ will not have E_STRICT in the error_reporting anymore you can state:
<?php
ini_set('error_reporting', (version_compare(PHP_VERSION, '5.3.0', '<') ? E_ALL|E_STRICT : E_ALL));
?>
Giving you all the error error reporting you want...
Please note that supplying an operator that is not listed (e.g. ===), this function returns NULL instead of false.
Tested on PHP5.3.0, Win32
Here's a wrapper which is more tolerant as far as order of arguments is considered:
<?php
function ver_cmp($arg1, $arg2 = null, $arg3 = null) {
static $phpversion = null;
if ($phpversion===null) $phpversion = phpversion();
switch (func_num_args()) {
case 1: return version_compare($phpversion, $arg1);
case 2:
if (preg_match('/^[lg][te]|[<>]=?|[!=]?=|eq|ne|<>$/i', $arg1))
return version_compare($phpversion, $arg2, $arg1);
elseif (preg_match('/^[lg][te]|[<>]=?|[!=]?=|eq|ne|<>$/i', $arg2))
return version_compare($phpversion, $arg1, $arg2);
return version_compare($arg1, $arg2);
default:
$ver1 = $arg1;
if (preg_match('/^[lg][te]|[<>]=?|[!=]?=|eq|ne|<>$/i', $arg2))
return version_compare($arg1, $arg3, $arg2);
return version_compare($arg1, $arg2, $arg3);
}
}
?>
It also uses phpversion() as a default version if only one string is present. It can make your code look nicer 'cuz you can now write:
<?php if (ver_cmp($version1, '>=', $version2)) something; ?>
and to check a version string against the PHP's version you might use:
<?php if (ver_cmp('>=', $version)) something; ?>
instead of using phpversion().
Note that both leading and trailing spaces on your version numbers can break version_compare().
Tested on PHP 5.6.8:
<?php
echo "\nShould be 0";
echo "\n '1.0.0-pl' vs. '1.0.0-pl' ---> " . version_compare('1.0.0-pl', '1.0.0-pl');
echo "\n '1.0.0-pl' vs. ' 1.0.0-pl' ---> " . version_compare('1.0.0-pl', ' 1.0.0-pl');
echo "\n ' 1.0.0-pl' vs. '1.0.0-pl' ---> " . version_compare(' 1.0.0-pl', '1.0.0-pl');
echo "\n '1.0.0-pl' vs. '1.0.0-pl ' ---> " . version_compare('1.0.0-pl', '1.0.0-pl ');
echo "\n '1.0.0-pl ' vs. '1.0.0-pl' ---> " . version_compare('1.0.0-pl ', '1.0.0-pl');
echo "\n\nShould be 1";
echo "\n '1.1.1-pl' vs. '1.0.0-pl' ---> " . version_compare('1.1.1-pl', '1.0.0-pl');
echo "\n ' 1.1.1-pl' vs. '1.0.0-pl' ---> " . version_compare(' 1.1.1-pl', '1.0.0-pl');
echo "\n\nShould be -1";
echo "\n '1.0.0-pl' vs. '1.1.1-pl' ---> " . version_compare('1.0.0-pl', '1.1.1-pl');
echo "\n '1.0.0-pl' vs. ' 1.1.1-pl' ---> " . version_compare('1.0.0-pl', ' 1.1.1-pl');
/* Output
Should be 0
'1.0.0-pl' vs. '1.0.0-pl' ---> 0
'1.0.0-pl' vs. ' 1.0.0-pl' ---> 1
' 1.0.0-pl' vs. '1.0.0-pl' ---> -1
'1.0.0-pl' vs. '1.0.0-pl ' ---> 1
'1.0.0-pl ' vs. '1.0.0-pl' ---> -1
Should be 1
'1.1.1-pl' vs. '1.0.0-pl' ---> 1
' 1.1.1-pl' vs. '1.0.0-pl' ---> -1
Should be -1
'1.0.0-pl' vs. '1.1.1-pl' ---> -1
'1.0.0-pl' vs. ' 1.1.1-pl' ---> 1
*/
