[PATCH doc/langref.tex] Add error probe information

[Robb Romans]

On Thu, 3 Sep 2009, Josh Stone wrote:

> On 09/03/2009 03:18 PM, Robb Romans wrote:
>> +\subsubsection{error}
>> +\index{error} The \emph{error} probe point is similar to the end
>> +probe, except the probe handler runs when the session ends if an error
>> +occurred.  In this case, an \texttt{end} probe is skipped, but each
>> +\texttt{error} probe is still attempted.  You can use an
>> +\texttt{error} probe to clean up or perform a final action on script
>> +termination. You can also numerically parametrize an \texttt{error}
>> +probe to set a sequence.
>
> The meaning of the sequence isn't really clear until its described in
> the next subsection for begin and end probes.  Perhaps the error
> sequence should be moved into that discussion?

It's similar to an end probe, which is why I put it immediately after that 
probe. If you think it's clearer, I'll move it below "begin and end probe 
sequence".

Here's a patch for that:


Signed-off-by: Robb Romans <robb@linux.vnet.ibm.com>
---
  doc/langref.tex |   18 ++++++++++++++++++
  1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/doc/langref.tex b/doc/langref.tex
index 3d08234..958e098 100644
--- a/doc/langref.tex
+++ b/doc/langref.tex
@@ -1053,6 +1053,24 @@ The user script \texttt{begin} probe defaults to sequence number zero, so
  the tapset \texttt{begin} probe will run first.


+\subsubsection{error}
+\index{error} The \emph{error} probe point is similar to the end
+probe, except the probe handler runs when the session ends if an error
+occurred.  In this case, an \texttt{end} probe is skipped, but each
+\texttt{error} probe is still attempted.  You can use an
+\texttt{error} probe to clean up or perform a final action on script
+termination. You can also numerically parametrize an \texttt{error}
+probe to set a sequence.
+
+Here is a simple example:
+\begin{vindent}
+\begin{verbatim}
+probe error { println ("Oops, errors occurred. Here's a report anyway.")
+              foreach (coin in mint) { println (coin) } }
+\end{verbatim}
+\end{vindent}
+
+
  \subsubsection{never}
  \index{never}
  The \texttt{never} probe point is defined by the translator to mean \emph{never}.
-- 
1.6.0.4


-- 
Robb Romans
IBM LTC Information Development
robb@linux.vnet.ibm.com