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<title>PTypes: streams: error handling</title>
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<p class="hpath"><a href="index.html">Top</a>: <a href="streams.html">Streams</a>: 
Error handling</p>
<p>When a recoverable error occurs during input/output operations, an exception 
of type <span class="lang">(estream*)</span> is thrown. The exception object 
contains an error message which can be shown to the user. The message is accessible 
through <span class="def">estream::get_message()</span>. </p>
<p>The example below shows how to catch an exception and recover normal execution 
of the program:</p>
<blockquote> 
<pre>#include <pstreams.h>

USING_PTYPES

infile f("somefile.txt");
try 
{
    f.open();
    while(!f.get_eof())
    <span class="comment">    // read the file...</span>
}
catch (estream* e) 
{
    perr.putline(e->get_message());
    delete e;
}
</pre>
</blockquote>
<p>The <span class="lang">estream</span> class provides a system error code in 
UNIX errno semantics through <span class="def">estream::get_code()</span>. On 
Windows most error codes are translated into corresponding UNIX errno codes. Less 
frequently occurring errors are translated to a generic errno code EIO. When an 
<span class="lang">estream</span> object returns EIO, the actual message string 
is constructed based on the status code of the stream. For example, if the status 
code was IO_OPENING, the error code was EIO, the message would be "Couldn't 
open <i>[filename]</i>". For explanations on what each errno code means, 
see comments in <span class="lang">src/piobase.cxx</span> source file.</p>
<p><span class="lang">Estream</span> also provides a reference to the stream object 
that raised the error condition through <span class="lang">estream::get_errstm()</span>.</p>
<p class="seealso">See also: <a href="streams.iobase.html">iobase</a>, <a href="streams.examples.html">Examples</a></p>
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Source at commit 209d6fa3805c created 11 years 7 months ago. By Nathan Adams, Updating tparray to use variants as array because tpodlist was causing variant data corruption

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