The 'Getargs::Long' module allows usage of named parameters in function
calls, along with optional argument type-checking. It provides an easy way
to get at the parameters within the routine, and yields concise
descriptions for the common cases of all-mandatory and all-optional
parameter lists.

The validation of arguments can be done by a structure-driven routine
getargs() which is fine for infrequently called routines (but should be
slower), or via a dedicated routine created and compiled on the fly the
fist time it is needed, by using the cgetargs() family (expected to be
faster).

The 'Log::Agent' module is used to report errors, which leaves to the
application the choice of the final logging method: to a file, to STDERR,
or to syslog.