=head1 Exceptions

Ermyth uses its own exceptions defined in F<util/exception.h>. The example
used in this document will be C<nullpointer_exception>.

=head2 Throwing an exception

To throw an exception, you generally have the following possible syntaxes:

=over

=item throw nullpointer_exception ()

Throw an empty exception.

=item throw nullpointer_exception (char const *fmt, ...)

Throw an exception with a message. This constructor takes varargs like
C<printf> does.

=item throw nullpointer_exception (SRCINF, char const *fmt, ...)

The same as above but include information about the current file, line and
function. exception::what () will look like this:

   file.C(#line): function (): your message

=back

=head2 Adding a new exception

Adding a new exception is as easy as adding a line of C<ADD_EXCEPTION (name, base_class)>.
The F<util/exception.h> file has examples of adding exceptions. C<base_class>
is the exception class from which you want to inherit. That way, you can create
an exception hierarchy within ermyth.

=head2 List of exceptions

=over

=item nullpointer_exception

Thrown whenever a pointer is a C<NULL> pointer where it definately should not be.
C<return_if_fail (ptr != NULL)> should be used in cases where the event is not
exceptional.

=item balloc_exception

Used internally by the block allocator for instance if there is no deallocator
available.

=item module_exception

Currently only thrown if two modules are trying to register themselves with
the same name.

=item factory_exception

Currently unused.

=back