#uninitialized

Use of uninitialized value in string — promoting warning to fatal error across Perl versions

The warning "Use of uninitialized value $var in string" fires whenever an undefined scalar is interpolated or concatenated. The core warnings pragma reports it but lacks a built-in mechanism to treat this specific category as fatal. Community discussions reference use warnings FATAL => 'uninitialized'; yet this syntax does not appear in the official perlw