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<H1>Section 11: Exceptions</H1>
<DIV Class="Paranum"><FONT SIZE=-2>1</FONT></DIV>
<DIV Class="Normal"> This section defines the facilities for dealing
with errors or other exceptional situations that arise during program
execution. <A NAME="I3820"></A><A NAME="I3821"></A><A NAME="I3822"></A><A NAME="I3823"></A><A NAME="I3824"></A><A NAME="I3825"></A>An
<I>exception</I> represents a kind of exceptional situation; an occurrence
of such a situation (at run time) is called an <I>exception occurrence</I>.
<A NAME="I3826"></A>To <I>raise</I> an exception is to abandon normal
program execution so as to draw attention to the fact that the corresponding
situation has arisen. <A NAME="I3827"></A>Performing some actions in
response to the arising of an exception is called <I>handling</I> the
exception. </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>2</FONT></DIV>
<DIV Class="Normal"> An <FONT FACE="Arial, Helvetica">exception_declaration</FONT>
declares a name for an exception. An exception is raised initially either
by a <FONT FACE="Arial, Helvetica">raise_statement</FONT> or by the failure
of a language-defined check. When an exception arises, control can be
transferred to a user-provided <FONT FACE="Arial, Helvetica">exception_handler</FONT>
at the end of a <FONT FACE="Arial, Helvetica">handled_sequence_of_statements</FONT>,
or it can be propagated to a dynamically enclosing execution. </DIV>
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