NAME
    Debian::Dpkg::Version - handling and comparing dpkg-style version
    numbers

DESCRIPTION
    The Debian::Dpkg::Version module provides pure-Perl routines to compare
    dpkg-style version numbers (as used in Debian packages) and also an
    object oriented interface overriding perl operators to do the right
    thing when you compare Debian::Dpkg::Version object between them.

OBJECT INTERFACE
    my $v = Debian::Dpkg::Version->new($version, %opts)
        Create a new Debian::Dpkg::Version object corresponding to the
        version indicated in the string (scalar) $version. By default it
        will accepts any string and consider it as a valid version. If you
        pass the option "check => 1", it will return undef if the version is
        invalid (see version_check for details).

        You can always call $v->is_valid() later on to verify that the
        version is valid.

    $v->is_valid()
        Returns true if the version is valid, false otherwise.

    $v->epoch(), $v->version(), $v->revision()
        Returns the corresponding part of the full version string.

    $v1 <=> $v2, $v1 < $v2, $v1 <= $v2, $v1 > $v2, $v1 >= $v2
        Numerical comparison of various versions numbers. One of the two
        operands needs to be a Debian::Dpkg::Version, the other one can be
        anything provided that its string representation is a version
        number.

    "$v" =item $v->as_string()
        Returns the string representation of the version number.

FUNCTIONS
    All the functions are exported by default.

    version_compare($a, $b)
        Returns -1 is $a is smaller than $b, 0 if they are equal and 1 if $a
        is bigger 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 non-numerical parts of
        version numbers. Returns -1 is $a is smaller than $b, 0 if they are
        equal and 1 if $a is bigger than $b.

        The "~" character always sort lower than anything else. Digits sort
        lower than non-digits. Among remaining characters alphabetic
        characters (A-Za-z) 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 sub-parts 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 non-digits items that are
        compared together. As soon as a difference happens, it returns -1 if
        $a is smaller than $b, 0 if they are equal and 1 if $a is bigger
        than $b.

    my @items = version_split_digits($version)
        Splits a string in items that are each entirely composed either of
        digits or of non-digits. For instance for "1.024~beta1+svn234" it
        would return ("1", ".", "024", "~beta", "1", "+svn", "234").

    my ($ok, $msg) = version_check($version) =item 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.

AUTHOR
    Don Armstrong <don@donarmstrong.com>, Colin Watson <cjwatson@debian.org>
    and Raphaël Hertzog <hertzog@debian.org>, based on the implementation
    in `dpkg/lib/vercmp.c' by Ian Jackson and others.