=head1 NAME

warnings - Perl pragma to control optional warnings

=head1 SYNOPSIS

    use warnings;
    no warnings;

    use warnings "all";
    no warnings "all";

    use warnings::register;
    if (warnings::enabled()) {
        warnings::warn("some warning");
    }

    if (warnings::enabled("void")) {
        warnings::warn("void", "some warning");
    }

    if (warnings::enabled($object)) {
        warnings::warn($object, "some warning");
    }

    warnings::warnif("some warning");
    warnings::warnif("void", "some warning");
    warnings::warnif($object, "some warning");

=head1 DESCRIPTION

The C<warnings> pragma is a replacement for the command line flag C<-w>,
but the pragma is limited to the enclosing block, while the flag is global.
See L<perllexwarn> for more information.

If no import list is supplied, all possible warnings are either enabled
or disabled.

A number of functions are provided to assist module authors.

=over 4

=item use warnings::register

Creates a new warnings category with the same name as the package where
the call to the pragma is used.

=item warnings::enabled()

Use the warnings category with the same name as the current package.

Return TRUE if that warnings category is enabled in the calling module.
Otherwise returns FALSE.

=item warnings::enabled($category)

Return TRUE if the warnings category, C<$category>, is enabled in the
calling module.
Otherwise returns FALSE.

=item warnings::enabled($object)

Use the name of the class for the object reference, C<$object>, as the
warnings category.

Return TRUE if that warnings category is enabled in the first scope
where the object is used.
Otherwise returns FALSE.

=item warnings::warn($message)

Print C<$message> to STDERR.

Use the warnings category with the same name as the current package.

If that warnings category has been set to "FATAL" in the calling module
then die. Otherwise return.

=item warnings::warn($category, $message)

Print C<$message> to STDERR.

If the warnings category, C<$category>, has been set to "FATAL" in the
calling module then die. Otherwise return.

=item warnings::warn($object, $message)

Print C<$message> to STDERR.

Use the name of the class for the object reference, C<$object>, as the
warnings category.

If that warnings category has been set to "FATAL" in the scope where C<$object>
is first used then die. Otherwise return.

=item warnings::warnif($message)

Equivalent to:

    if (warnings::enabled())
      { warnings::warn($message) }

=item warnings::warnif($category, $message)

Equivalent to:

    if (warnings::enabled($category))
      { warnings::warn($category, $message) }

=item warnings::warnif($object, $message)

Equivalent to:

    if (warnings::enabled($object))
      { warnings::warn($object, $message) }

=back

See L<perlmodlib/Pragmatic Modules> and L<perllexwarn>.

=cut
