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<P><FONT SIZE="5">8.2 Return Statuses</FONT><BR>
<P>The hierarchy of diagnostics is also used in the shell
commands. Each shell command returns a status which can
affect further processing.
<P><BLOCKQUOTE><B>Success</B> status is the normal command
return status.</BLOCKQUOTE>
<P><BLOCKQUOTE><B>Warning</B> status is returned if some minor
problem arose with the execution of the command.</BLOCKQUOTE>
<P><BLOCKQUOTE><B>Error</B> status is returned if a significant
problem arises during the execution of the command. However,
unlike a severe error, it does <I>not</I> cause
termination of the enclosing shellscript.</BLOCKQUOTE>
<P><BLOCKQUOTE><B>Severe error</B> status is returned if a
problem arises during the execution of the command that
prevents the command from delivering on its
"promise". A severe error causes FunnelWeb to abort
the script (and any stacked scripts) to the interactive
level. (However, the <SAMP>tolerate</SAMP> command allows this
to be temporarily overridden).</BLOCKQUOTE>
<P><BLOCKQUOTE><B>Fatal error</B> status is returned if a
problem arises that is so serious that execution of
FunnelWeb cannot continue. A fatal error causes FunnelWeb to
abort to the operating system level.</BLOCKQUOTE>
<P><BLOCKQUOTE><B>Assertion error</B> status is never returned.
If an assertion error occurs, FunnelWeb bombs out
ungracefully to the operating system. Assertion errors
should never happen. If they do, then there is a bug in
FunnelWeb.</BLOCKQUOTE>
<P>To be precise, the status returned by each command is a
vector of numbers being the number of each of the different
kinds of diagnostic generated by the command. Usually only
one kind of diagnostic is generated. However, the
<SAMP>fw</SAMP> command and a few of the other commands can
generate more than one kind of diagnostic. These status
vectors are summed internally where they may later be
accessed using the <SAMP>status</SAMP> command. However, the
current diagnostic state evaporates as soon as the next
command is encountered.
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