### try.pl ###
use strict;
use warnings;

use Inline C => <<'EOC';

void foo() {
  Perl_ck_warner_d(aTHX_ packWARN(WARN_LOCALE),
                   "Locale is unsupported, and may crash the"
                   " interpreter.\n"
                  );
}

void bar() {
  Perl_ck_warner_d(aTHX_ packWARN(WARN_LOCALE),
                   "Locale is unsupported, and may crash the"
                   " interpreter"
                  );
}

EOC

foo();
bar();

__END__

Outputs:
Locale is unsupported, and may crash the interpreter.
Locale is unsupported, and may crash the interpreter at try.pl line 24.