Hi Ken
Thanks for pointing this out. I'd always assumed that uncaught exception
messages got printed (they do for me) so was happy to have them float up the
stack.
Adding such a terminate handler seems like a good idea. Are there any
unexpected consequences? Are you just proposing to add it to the main moses
binary?
btw there's a school of though which says you shouldn't use exceptions, but I
don't subscribe to it. I think maybe this is because in the early days of C++
exceptions didn't work properly or had performance problems. Or maybe because
google said not to use them.
cheers
Barry
On Wednesday 23 Feb 2011 20:30:27 Kenneth Heafield wrote:
> Hiya Moses,
>
> There are a fair number of exceptions thrown that are not intended to
> be caught e.g. Sentence.cpp: 107:
>
> if (!ProcessAndStripXMLTags(line, xmlOptionsList,
> m_reorderingConstraint, xmlWalls )) {
> const string msg("Unable to parse XML in line: " + line);
> TRACE_ERR(msg << endl);
> throw runtime_error(msg);
>
> I use them extensively in kenlm for file formatting issues. When an
> exception is thrown and nothing catches it (i.e. the stack unwinds past
> main), GCC typically prints the type of the exception and the .what()
> string. However, the C++ standard only requires an abort() when this
> happens. Therefore some users, apparently including Nicola Bertoldi, do
> not see the .what() message and only see an opaque "Aborted" message.
>
> The solution is to link in a file like this:
>
> #include <cstdlib>
> #include <exception>
> #include <iostream>
>
> namespace {
>
> void terminate_handler() {
> try { throw; }
> catch(const std::exception& e) {
> std::cerr << e.what() << std::endl;
> }
> catch(...) {
> std::cerr << "A non-standard exception was thrown." << std::endl;
> }
> std::abort();
> }
>
> struct ForceCall {
> ForceCall() { std::set_terminate(terminate_handler); }
> };
> const ForceCall kForceCall;
>
> } // namespace
>
> This overrides the default handler so that the message is always
> printed. It might be preferable to still print the type if RTTI is
> available.
>
> Alternatively, main() could just be wrapped in a try/catch block; that
> would work in most cases except static/global constructors and
> destructors. There are 34 main() functions.
>
> Should I link this into the main moses binary?
>
> Kenneth
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>
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