my $MAX_BYTES = 25;
my ($MIN_BPC, $MAX_BPC) = (1, 4);
my $MAX_CHARS = $MAX_BYTES / $MIN_BPC;

##</code><code>##

D:\>perl -CO -Mcharnames=:full -wE "$MAX = 4; $cafe = qq/cafe\N{COMBINING ACUTE ACCENT}/; say $cafe; substr($cafe, $MAX) = ''; say $cafe;" > cafe.txt

D:\>