The Mail::Box::Parser::C implements parsing of messages in ANSI C, using Perl's XS extension facility. This is an optional module for MailBox, and will (once installed) automatically be used by MailBox to parse e-mail message content when the message is supplied as file-handle. In all other cases, MailBox will use Mail::Box::Parser::Perl. WWW: https://metacpan.org/release/Mail-Box-Parser-C