Re: Writing triggers in C++ - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: Writing triggers in C++
Date
Msg-id 20070214132026.GG5025@alvh.no-ip.org
Whole thread Raw
In response to Re: Writing triggers in C++  ("Florian G. Pflug" <fgp@phlo.org>)
Responses Re: Writing triggers in C++  ("Florian G. Pflug" <fgp@phlo.org>)
List pgsql-hackers
Florian G. Pflug wrote:
> Andreas Pflug wrote:
> >Tom Lane wrote:
> >>Jacob Rief <jacob.rief@gmx.at> writes:
> >>  
> >>>I tried to write a trigger using C++.
> >>>    
> >>That is most likely not going to work anyway, because the backend
> >>operating environment is C not C++.  If you dumb it down enough
> >>--- no exceptions, no RTTI, no use of C++ library --- then it might
> >>work, 
> >I can confirm that it does work this way.
> 
> I've written an aggregate function that uses c++ stl hashes, and it 
> seems to work pretty well. I'd think that using exceptions should be
> fine, as long as you make sure to _always_ catch any exception that
> might be thrown inside your own c++ code, and don't let it propagate
> into backend code. STL allows you to specify custom allocator classes
> as template parameters to hash, vector and the like. You can use that
> to let STL allocate memory from the correct memory context.

What happens if Postgres raises an elog(ERROR) in the code you're
catching exceptions in?  Is it propagated outwards?

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.


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