The C<IO::Capture> Module defines an abstract base class that can be
used to build modules that capture output being sent on a filehandle
such as STDOUT or STDERR.
  Several modules that come with the distribution, do just that.
(I.e., Capture STDOUT and STDERR)  See L<IO::Capture::Overview> for a
discussion of these modules and examples of how to build a module to
sub-class from C<IO::Capture> yourself.   If after reading the overview,
you would like to build a class from C<IO::Capture>, look here for
details on the internals.