Re: Error handling in a parser (return value or setjmp)

From	Ian Collins <ian-news@hotmail.com>
Newsgroups	comp.lang.c
Subject	Re: Error handling in a parser (return value or setjmp)
Date	2015-10-14 16:31 +1300
Message-ID	<d860ldFlf7cU7@mid.individual.net> (permalink)
References	(11 earlier) <mvk6lg$fj4$1@speranza.aioe.org> <07er1bts21ei5nm19fqj5alu46puf19emr@4ax.com> <mvkegm$sac$1@speranza.aioe.org> <d85v3dFlf7cU6@mid.individual.net> <mvkhgv$1e6$1@speranza.aioe.org>

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Morten W. Petersen wrote:
> On 14.10.2015 05:05, Ian Collins wrote:
>> Morten W. Petersen wrote:
>>
>>> It's about planning ahead and making less work for myself.  There are
>>> different styles to working, mine works for me.
>>
>> http://martinfowler.com/bliki/Yagni.html
>>
>>> As for threading, it is also something that has to be taken into
>>> account, and I'm already designing the main parser loop so that
>>> threading can be plugged in there.  I know now that using pthreads
>>> and a specific exception library looks like a good idea, and that's
>>> nice to know, before I decide on ways to deal with errors and
>>> choose something I'll end up typing a lot of characters to change.
>>
>> All of the research backed by my own testing shows that threading
>> doesn't really have a place in XML parsing.  The housekeeping overheads
>> dominate.
>
> OK.  What are the housekeeping overheads?

Many, but mainly context switching and synchronising the output of the 
threads.  Are you building a DOM?  If so you would have tn make access 
to it thread safe which will incur a cost.

> Right now there might not be much use for the threading in my library
> either.
>
> But maybe I move the Unicode validation into the main parsing loop,
> maybe make some changes here and there.
>
> The sets of characters that make up the "main" markup are very
> limited and can be checked for, then the rest offloaded to a
> function that might be threaded.  What I need is really a super
> simple threading library that can be handed a function and finish
> it, and maybe I need a counter for active threads.  That's it.

Even with a simple thread pool, you still have devise a synchronising 
mechanism to had over work and receive processed data.  You also have to 
accept the overhead of context switching.  Simple and threading don't 
normally appear in the same sentence!

-- 
Ian Collins

Thread

Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-13 04:33 +0200
  Re: Error handling in a parser (return value or setjmp) Ian Collins <ian-news@hotmail.com> - 2015-10-13 15:54 +1300
    Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-13 05:07 +0200
  Re: Error handling in a parser (return value or setjmp) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-13 14:07 +0100
    Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-13 16:17 +0200
    Re: Error handling in a parser (return value or setjmp) supercat@casperkitty.com - 2015-10-13 08:26 -0700
      Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-13 18:14 +0200
        Re: Error handling in a parser (return value or setjmp) Ian Collins <ian-news@hotmail.com> - 2015-10-14 07:46 +1300
          Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-13 22:06 +0200
            Re: Error handling in a parser (return value or setjmp) Ian Collins <ian-news@hotmail.com> - 2015-10-14 10:32 +1300
              Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-13 23:47 +0200
                Re: Error handling in a parser (return value or setjmp) Ian Collins <ian-news@hotmail.com> - 2015-10-14 11:02 +1300
                Re: Error handling in a parser (return value or setjmp) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-14 18:32 +0000
                Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-15 12:28 +0200
                Re: Error handling in a parser (return value or setjmp) Ian Collins <ian-news@hotmail.com> - 2015-10-16 07:47 +1300
            Re: Error handling in a parser (return value or setjmp) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-13 21:39 +0000
              Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-13 23:49 +0200
                Re: Error handling in a parser (return value or setjmp) supercat@casperkitty.com - 2015-10-13 15:03 -0700
                Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-14 01:16 +0200
                Re: Error handling in a parser (return value or setjmp) Geoff <geoff@invalid.invalid> - 2015-10-13 16:46 -0700
                Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-14 02:13 +0200
                Re: Error handling in a parser (return value or setjmp) Geoff <geoff@invalid.invalid> - 2015-10-13 19:10 -0700
                Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-14 04:27 +0200
                Re: Error handling in a parser (return value or setjmp) Ian Collins <ian-news@hotmail.com> - 2015-10-14 16:05 +1300
                Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-14 05:18 +0200
                Re: Error handling in a parser (return value or setjmp) Ian Collins <ian-news@hotmail.com> - 2015-10-14 16:31 +1300
                Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-14 05:44 +0200
                Re: Error handling in a parser (return value or setjmp) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-15 12:06 +0000
                Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-15 16:08 +0200
                Re: Error handling in a parser (return value or setjmp) supercat@casperkitty.com - 2015-10-14 00:36 -0700
                Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-15 12:32 +0200
                Re: Error handling in a parser (return value or setjmp) Ian Collins <ian-news@hotmail.com> - 2015-10-14 11:06 +1300
                Re: Error handling in a parser (return value or setjmp) David Brown <david.brown@hesbynett.no> - 2015-10-14 00:10 +0200
                Re: Error handling in a parser (return value or setjmp) James Kuyper <jameskuyper@verizon.net> - 2015-10-13 19:08 -0400
              Re: Error handling in a parser (return value or setjmp) raltbos@xs4all.nl (Richard Bos) - 2015-10-14 11:37 +0000
                Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-15 12:34 +0200
                Re: Error handling in a parser (return value or setjmp) Ian Collins <ian-news@hotmail.com> - 2015-10-16 07:56 +1300
                Re: Error handling in a parser (return value or setjmp) "Morten W. Petersen" <morphex@gmail.com> - 2015-10-16 05:45 +0200
            Re: Error handling in a parser (return value or setjmp) James Kuyper <jameskuyper@verizon.net> - 2015-10-13 18:53 -0400

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