Does declaring an array of lambda functions with reference captures cause Heap Allocation?-CodePudding

Recently, I am told that declaring an array of lambda functions with reference captures cause Heap allocation. I don't see how this could be true. If true, how and is it possible to do refactoring to avoid Heap Allocation?

For visualization purposes:

std::function<void(void)> func1 = [a few ref captures here](no argument) -> void { ... }
std::function<void(void)> func2 = [a few different ref captures here](no argument) -> void { ... }
std::function<void(void)> func3 = [a few different ref captures here](no argument) -> void { ... }

std::array<std::function<void(void)>, 3U> func_array{ func1, func2, func3 };

CodePudding user response：

You're dynamic allocation comes from your use of std::function<void(void)> which uses dynamic allocation for type erasure.

You would need to refactor the std::functions out and that's going to be really hard / potentially impossible to do as your closures have different types.