Re: [Boost-users] What's wrong with this simple multithreaded function that uses regex?

Subject: Re: [Boost-users] What's wrong with this simple multithreaded function that uses regex?
From: Andrew Yancy (andrew732_at_[hidden])
Date: 2011-08-02 17:00:40

>I don't see anything obviously wrong with that.  My only question, is you
>say BOOST_HAS_THREADS is defined, are you defining it, or is Boost.Config
>defining it (if Boost.Config *isn't* setting it, then your project >settings
>are wrong for multithreaded code)?  Are you selecting the regex lib to >link
>to manually or letting the auto-linking code do it's work (for minimum
>chances of bad things happening you should let the auto-linking code >select
>the correct binary)?
>HTH, John. 

>You should use _beginthread or _beginthreadex to start C++ thread when >using
>MSVC.
>CreateThread is too low level and does not do the per thread >initialization
>required. If you read MSDN documentation it explain why CreateThread >cannot
>be use with C++ program.
>Daniel Anderson

Thanks for the replies John and Daniel.  I've reinstalled boost 1.47 making sure that all the multithreaded options were built and am using _beginthreadex() now, but the exact same problem seems to occur where the code snippet below crashes if and only if boost::regex_match() is called.  I am not defining BOOST_HAS_THREADS in my code, it is defined automatically although I'm not sure how exactly.  Also, as far as I know I am not manually linking to the necessary libraries; all I do is tell MSVC to look in "C:\Program Files\boost\boost_1_47_0\stage\lib" for additional libraries so presumably it chooses whichever one it needs.  There are no thread or boost-related warnings in the build.

Any other ideas?  I really appreciate the help~

...
static const boost::regex expression("^[0-9]+");
ifstream myfile(x); //x is a different file name for every thread
string line;
if(myfile.is_open())
{
  while(myfile.good())
  {
     getline(myfile, line);
     if(boost::regex_match(line, expression))
     {
        //do stuff
     }
  }
  myfile.close();
}
...