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warnings
Perl pragma to control optional warnings

warnings - Perl pragma to control optional warnings


NAME

warnings - Perl pragma to control optional warnings


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");


DESCRIPTION

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

A number of functions are provided to assist module authors.

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

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.

warnings::enabled($category)
Return TRUE if the warnings category, $category, is enabled in the calling module. Otherwise returns FALSE.

warnings::enabled($object)
Use the name of the class for the object reference, $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.

warnings::warn($message)
Print $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.

warnings::warn($category, $message)
Print $message to STDERR.

If the warnings category, $category, has been set to ``FATAL'' in the calling module then die. Otherwise return.

warnings::warn($object, $message)
Print $message to STDERR.

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

If that warnings category has been set to ``FATAL'' in the scope where $object is first used then die. Otherwise return.

warnings::warnif($message)
Equivalent to:

    if (warnings::enabled())

      { warnings::warn($message) }

warnings::warnif($category, $message)
Equivalent to:

    if (warnings::enabled($category))

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

warnings::warnif($object, $message)
Equivalent to:

    if (warnings::enabled($object))

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

See perlmodlib/Pragmatic Modules and perllexwarn.

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