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Subject: Re: [Boost-users] [multi_index] doing insert() within iteration over equal_range() result?
From: joaquin_at_[hidden]
Date: 2008-10-23 10:50:15

Prometheus Prometheus escribió:
> Hi all,
> i have the following problem:
> i use multi_index like this
> std::pair<Plugins::pEvents::index::type::iterator,Plugins::pEvents::index::type::iterator> range;
> range = this->events.get().equal_range(boost::make_tuple(event,condition));
> while(range.first!=range.second){
> // CALL an event handler!
> this->callEventHandler(range.first); // << this shows just how it works, its not exactly my code
> ++range.first;
> }
> within the callEventHandler and its called functions its possible that the event handler wants to register new events which results to this:
> this->events.insert(eventdata);
> The problem is OR can be, that the insert modifies the indices which modify the range.first iterators and thus a ++range.first results in an invalid "next" element
> this makes sense and i think most of you know this and had this problem already
> Questions:
> Does anyone have a good idea/solution how to solve this situation correctly so that the range i received will be valid?

I think the easiest solution is to save copies of the iterators in range
before you
start the loop:

  range = this->events.get().equal_range(boost::make_tuple(event,condition));

  std::vector<Plugins::pEvents::index::type::iterator> buff;

  for(std::size_t n=0,s=buff.size();n<s;++n){
    // CALL an event handler!


Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

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