RE: [Dev-C++] STL Map question

[Jaap de W. <wo...@ne...>]

Hmm, I had problems like this also.
Are you using a multithreaded environment?
Is it possible that sometimes two threads at the same time are accessing the
map, 
one for removing a key, and one for finding a key?

Jaap

> -----Original Message-----
> From: Shane Bryldt [mailto:ast...@te...]
> Sent: Friday, July 11, 2003 10:53 PM
> To: Hossein Haeri
> Cc: C++
> Subject: Re: [Dev-C++] STL Map question
> 
...
> 
> Now, the effect of the issue, is as follows. A network of 6,000-10,000
> active users at any given time is regulated by a security 
> service.  This
> service runs and connects like a user, with special 
> priviledges.  Anytime a
> user connects to the network, the services is informed, and 
> the User is
> added to a global UserList.  The network also has smaller 
> units, known as
> Channels.  Each Channel contains 3 UserList's as well.  
> First, depicts all
> users in the Channel, the second depicts all the operators of 
> the channel,
> and the third depicts the priviledged users who are not 
> operators.  99% of
> the time, the code work fine.  Users constantly added and 
> removed from the
> list.  Periodically, what seems like an issue without a 
> pattern, the code
> will crash with a segmentation fault while trying to call
> "std::map<>::find()", with a valid key.  Whether the key is 
> in the map, is
> not definate, but the key passed in valid and should not have 
> a problem
> being searched.
> 
> This said, I have narrowed the issue down to one of 2 causes. 
> 1) Either
> User's are being added to lists, and not being removed, and 
> the UserLists
> are eventually gathering enough garbage that out of memory is being
> encountered. The application has a signal hook for out of 
> memory, and it is
> not being raised.  So I am leaning more towards option 2) The 
> User class is
> being deleted, without being removed from the UserList.  
> However, I can find
> no indication of this in the code.  The code is many 
> thousands of lines, it
> is not a small project by any means.  Providing the source 
> for the issue,
> would require the entire project as the issue is not 
> specifically a syntax
> issue, but rather a situational issue.  I do believe something has
> invalidated a User class, which a UserList has a pointer to, 
> and when trying
> to use it, is causing a segmentation fault.  I'm sure most of 
> the experts
> here will agree with my conclusion and realize tracing this 
> problem is no
> easy task.
> 
> 
...