 version_compare($a, $b)

Returns 1 if $a is earlier than $b, 0 if they are equal and 1 if $a
is later than $b.
If $a or $b are not valid version numbers, it dies with an error.
 version_compare_relation($a, $rel, $b)

Returns the result (0 or 1) of the given comparison operation. This
function is implemented on top of version_compare().
Allowed values for $rel are the exported constants REL_GT, REL_GE,
REL_EQ, REL_LE, REL_LT. Use version_normalize_relation() if you
have an input string containing the operator.
 my $rel = version_normalize_relation($rel_string)

Returns the normalized constant of the relation $rel (a value
among REL_GT, REL_GE, REL_EQ, REL_LE and REL_LT). Supported
relations names in input are: ``gt'', ``ge'', ``eq'', ``le'', ``lt'', ``>>'', ``>='',
``='', ``<='', ``<<''. ``>'' and ``<'' are also supported but should not be used as
they are obsolete aliases of ``>='' and ``<=''.
 version_compare_string($a, $b)

String comparison function used for comparing nonnumerical parts of version
numbers. Returns 1 if $a is earlier than $b, 0 if they are equal and 1 if $a
is later than $b.
The ``~'' character always sort lower than anything else. Digits sort lower
than nondigits. Among remaining characters alphabetic characters (AZaz)
sort lower than the other ones. Within each range, the ASCII decimal value
of the character is used to sort between characters.
 version_compare_part($a, $b)

Compare two corresponding subparts of a version number (either upstream
version or debian revision).
Each parameter is split by version_split_digits() and resulting items
are compared together.in digits and nondigits items that are compared
together. As soon as a difference happens, it returns 1 if $a is earlier
than $b, 0 if they are equal and 1 if $a is later than $b.
 my @items = version_split_digits($version)

Splits a string in items that are each entirely composed either
of digits or of nondigits. For instance for ``1.024~beta1+svn234'' it would
return (``1'', ``.'', ``024'', ``~beta'', ``1'', ``+svn'', ``234'').
 my ($ok, $msg) = version_check($version)

 my $ok = version_check($version)

Checks the validity of $version as a version number. Returns 1 in $ok
if the version is valid, 0 otherwise. In the latter case, $msg
contains a description of the problem with the $version scalar.