Possible problem with iterators in STL

[babak]

Hi everyone
I have a problem with Iterators and Containers in STL that hopefully
someone can help me with.
This is what I try to do:

I have an associative (map) container and I have a function where I
with the help of iterators want to search through the container and
remove a certain object in the container.
Here is part of the code in that function:

//Move from timers map container to stale list container
Timers::iterator start(_timers.begin());
Timers::iterator last(_timers.end());


while (start != last)
{
if(compObj.Compare(start->second))
{
_stale.push_back(start->second);

start = _timers.erase(start);

}
else
{
++start;
}
}

The function works correctly most of the time (maybe 8 out of 10
times). It then goes through the while loop 3 times. The first time it
goes into the if case and erases the object and the other 2 times it
goes to the else case and then it jumps out of the while loop.
But sometimes it does not behave correctly. In those cases it behaves
like I described above until the third time in the while loop. The
function then goes to the else case but never leaves it (i.e it comes
to the line before ++start but not the line after it when I use
printfs).

I believe that all the initializations are made correctly so the only
thing I can come up with is that something goes wrong with the
iterator. Is there any possibility that I somehow e.g try to increase
the iterator out of bounds or make some other error which could lead to
very strange behaviour? Any other suggestions of what could lead to
this strange behaviour?

Thanks for your help.
Regards.
/Babak

 

[Vladimir Nesterovsky]

//Move from timers map container to stale list container

Timers::iterator start(_timers.begin());
Timers::iterator last(_timers.end());

while (start != last)
{
if(compObj.Compare(start->second))
{
_stale.push_back(start->second);

start = _timers.erase(start);

}
else
{
++start;
}
}

Any other suggestions of what could lead to this strange behaviour?

If it's not a problem with multithreading or with using map in different
dll, then I can think of code that works with _timers (within loop) that you
have omitted in your example.