attrs

Sets or gets the attributes of subroutines. Attributes are set for a subroutine at compile time; therefore, setting an invalid attribute results in a compile-time error. During execution, when you call attrs::get on a subroutine reference or name, it returns the list of attributes that are set. Note that attrs::get is not exported. For example:

sub test {
 use attrs qw(locked method); ...
}
@a = attrs::get(\foo);

• locked
• Meaningful only when the subroutine or method is to be called by multiple threads. When set on a subroutine that also has the method attribute set, invoking that subroutine implicitly locks its first argument before execution. On a non-method subroutine, a lock is taken on the subroutine itself before execution. The lock semantics are identical to one taken explicitly with the lock operator immediately after entering the subroutine.
• method
• The invoking subroutine is a method.