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Question: Is it a don't do it that delete a element of map in a loop?
//std::set<Battle::BattleBuf *> m_bufs; for (auto& pBuf : m_bufs) { pBuf->doEffect(pDef, param); // It can a deep call stack, and may call m_bufs.erase if(pBuf == nullptr || m_bufs.empty()) { ERROR_LOG("condbuffs is empty"); return; } }Iterator may invalidate during the ranged for loop. There's a naive solution, doEffect() can return the iterator returned by erase. But since it could be a deep call stack, it's almost impossible. How to solve this problem, or it's just a design red flag. It's hard to track whether it may cause invalidation when writing code.
Background: I maintain a skill module in game, a buff may have dismiss buffs effect
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The code does not utilize iterators. You should use them and a next iterator.
for (auto it = m_bufs.begin(); it != m_bufs.end(); ;) { auto *cur = *it++; cur->doEffect(pDef, param); }This specific code in the Q can be made a bit shorter
for (auto it = m_bufs.begin(); it != m_bufs.end(); ;) { (it++)->doEffect(pDef, param); }
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3 Comments
OK, I understand. References and iterators to the erased elements are invalidated. Other references and iterators are not affected.
2026-02-04T06:50:15.207Z+00:00
What if it may erase several elements, so it should take another design?
2026-02-04T06:53:25.453Z+00:00
You can iterate through a copy of the map. Or, don't erase but reset deleted elements to nullptr and clean the map after the loop.
2026-02-04T06:58:25.233Z+00:00
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