All other exit codes will be treated as a temporary failure and the delivery will be retried. There is no default. If this option is not specified, the h option must be. There is no default. If this option is not specified, the c option must be.
V prints a version message and exits.
The configuration file associates the mailer keyword from the command line with a specification of a delivery program. This is very similar to the way the definition of a mailer in Sendmail requires flags, a program name, and a command line specification. These are in fact the fields of the entries of the configuration file. The mailer field extends from the beginning of the line to the first whitespace. It is used simply as a key index to the configuration file contents.