[Fwd: Re: Thread Safe Lexer]

[Behdad Forghani <behdad.forghani () samsarasol com>]

Hello,

Gianluca asked me to forward this to the mailing list. During 
Sharkfest09 he had mentioned that Winpcap cannot is not re-entrant and 
thread-safe because Lex uses global variables. As you can see, one 
solution to this is to use re2c for lexing and lemon for parsing. The 
link to re2c is:
http://re2c.org/
http://sourceforge.net/projects/re2c/

Let me know if you want me to help any further.

Best Regards,
Behdad

----- Original Message ----- 
From: "Behdad Forghani" <behdad.forghani () samsarasol com>
To: <gianluca.varenni () cacetech com>
Sent: Monday, June 29, 2009 12:53 PM
Subject: Thread Safe Lexer


> Hi Gianluca,
>
> As you remembered, we discussed thread safe lexer during Sharkfest. You 
> can use flex++ to generate C++ code that is thread safe. If you want more 
> information let me know.
>
> Another good tool to make thread safe lexers is re2c.

Using flex++ is probably a no/no, since it generates C++, and libpcap is 
strictly C code.
How many changes would be needed to use re2c instead of flex/bison?

Also, I think it would be great to move this discussion to the 
tcpdump-workers mailing list, where all the libpcap folks hang out.

Have a nice day
GV

> I had wrongly mentioned lemon, lemon generates thread safe parser and not 
> lexer.
>
> Let me know if you need any help.
>
> Regards,
> Behdad 


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