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

       The "warnings" pragma is a replacement for the command line flag "-w", but the pragma is limited to the
       enclosing block, while the flag is global.  See perllexwarn for more information and the list of built-in
       warning categories.

       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::fatal_enabled()
           Return  TRUE if the warnings category with the same name as the current package has been set to FATAL
           in the calling module.  Otherwise returns FALSE.

       warnings::fatal_enabled($category)
           Return TRUE if the warnings category  $category  has  been  set  to  FATAL  in  the  calling  module.
           Otherwise returns FALSE.

       warnings::fatal_enabled($object)
           Use the name of the class for the object reference, $object, as the warnings category.

           Return  TRUE  if  that warnings category has been set to FATAL 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) }

       warnings::register_categories(@names)
           This  registers  warning  categories  for  the  given  names  and  is  primarily  for  use   by   the
           warnings::register pragma, for which see perllexwarn.

       See "Pragmatic Modules" in perlmodlib and perllexwarn.

perl v5.18.2                                       2014-01-06                                    warnings(3perl)