Re: [Boost-users] Boost::Regex - bug work-around...?

From: Michael Starling (mstarling_at_[hidden])
Date: 2004-10-29 08:12:18

I apologize, I realized after I sent it that there may have been more involved in the problem than I initially thought - I'm pretty sure the program's dying during the function calls, but as you point out, it may be just the rest of my program being lax with memory and using it all up, precipitating the problem.  I was just getting frustrated and sometimes a night to sleep on it can help - I will try to double-check all the code, particularly the functions that allocate memory for the file contents (which then gets fed to RegEx...), and what values are getting passed to the library functions.  If I still can't figure it out I'll try to do a more thorough trace.
 
Despite that (which may well just be my own bad code from a long tiring day), I've been really impressed with the regex library, thank you for your work on it.
 
Mike.
 

John Maddock <john_at_[hidden]> wrote:
> I've been trying to implement some routines using the Boost library, 
> primarily with the excellent RegEx library. Everything was working well 
> enough in small tests, but when I tried running the routines on many 
> patterns, my program would crash (it performs various pattern matching and 
> search-and-replaces in multiple text files). I was able to determine that 
> the crashes came on the calls to regex-related functions (though it tended 
> to be a little unpredictable as to when, depending on the set of files I 
> gave it).
>
> I tried changing my project settings (I use VC6, btw) to link with "debug" 
> libraries instead of the standard ones (eg. "Debug Multithreaded"), and 
> ran the program again, and everything worked perfectly.
>
> Unfortunately... I don't want to have my program running with all-debug 
> libraries for performance and size reasons. However, is it possible to 
> have my link-settings set to use standard libraries as before, but for the 
> stuff that uses the regex library, to use a debug ".lib" file? Or... in 
> the 'bjam' process, is it possible to say something to the effect of "when 
> compiling the regex libraries, turn off compiler optimizations", so I can 
> get a standard library that should work...?

I think you really need to track down the cause of the problem before 
blaming it on regex or the compiler.

Some possible options:

You're passing a temporary to one of the regex functions and getting 
out-of-date invalidated iterators back.
You're using some data that's uninitialised (zero initialised in bebug mode, 
but garbage in release mode).

Also don't forget that you can put debug information in an otherwise release 
build, and then debug it.

You can also add the regex source directly to your project (but define 
BOOST_REGEX_NO_LIB project-wide to suppress auto-linking), and control 
options from there if it comes to it.

John. 

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