Re: [Boost-users] Tracking down a race condition

Subject: Re: [Boost-users] Tracking down a race condition
From: Roland Bock (rbock_at_[hidden])
Date: 2010-01-26 02:48:26

Stephen Torri wrote:
> On Mon, 2010-01-25 at 19:38 +0100, Roland Bock wrote:
> 
>> You can see what is happening by making the writing of logs slower:
>>
>>     void Trace::threadMain()
>>     {
>>        boost::this_thread::sleep(boost::posix_time::seconds(1)); // 
>> Insert this
>>       boost::unique_lock<boost::mutex> lock ( m_lock );
>> ...
> 
> I made it slower adding in the line. I did not see anything in the
> output. How did you observe the program after adding that line? Did you
> use a debugger or just execute it?

Hi,

if I read your original code correctly, you have two threads: one closes 
the file, one wants to write to it. If you have a racing condition, you 
can often see a change by making one thread slower. And voila, there is 
a change: Instead of something getting an empty log file, you now always 
get an empty log file (the close always wins the race).

No debugger needed for this.

Regarding your new problem: Please try to isolate the problem in code 
that compiles and consists of a few dozen lines (the less, the more 
probable that someone will take the time to read it).

Regards,

Roland