Keeping std::list iterators valid through insertion

Question

Note: This is not a question whether I should \"use list or deque\". It\'s a question about the validity of iterators in the face of insert().

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Answer 1

if (readpos == buf.begin())
{
    buf.insert(buf.end(), newdata.begin(), newdata.end());
    readpos = buf.begin();
}
else
{
    --readpos;
    buf.insert(buf.end(), newdata.begin(), newdata.end());
    ++readpos;
}

Not elegant, but it should work.