(PHP 4 >= 4.1.0)

version_compare --  Compares two "PHP-standardized" version number strings


int 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.

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 1 if the relationship is the one specified by the operator, 0 otherwise.

Example 1. version_compare() Example

// 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");