Почему моя ссылка в захвате find_if вызывает проблемы с рендерингом в окне [закрыто] ⇐ C++

[Гость]

Я использую

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find_if

in Visual Studio with CL to locate a specific touch/finger in a vector, and the capture is an object that contains a reference to a finger with an ID. The basic idea is that I have a list of fingers, each with an ID, and I want to find the one that matches the ID of the current finger. When I do this manually or pass in the ID, it works, but the following

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find_if

is causing a visual issue, so I'm thinking it's corrupting the memory/undefined behavior.

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auto Finger::dataRef() const -> FingerData const &
{
return fingerData; // member variable, and lifetime is the lifetime of the program
}

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auto findTap(
std::vector & taps,
controls::FingerData const & finger
) -> std::vector::iterator
{
return std::find_if(begin(taps), end(taps), [&](Tap & t) {
return t.getFingerId() == finger.fingerId;
});
}

I'm calling it like this:

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auto tap = findTap(taps, finger.dataRef());

If I inline the code and break out the finger ID like this, it solves the issue:

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auto & fId = x.fingerId;
auto tap = std::find_if(begin(taps), end(taps), [&](auto & t) {
return t.getFingerId() == fId;
});
auto tap = findTap(taps, finger.dataRef());

I haven't tried a different compiler. Am I misunderstanding something about the lambda here? I also tried creating a

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reference_wrapper

to the finger and passing that in instead, but it didn't solve the issue.
I tried different ways to pass in the finger, but the only approach that solves my problem is to create a reference to the finger ID outside the lambda and then use that directly.
This first video is from MSVC, which is causing rapid flickering that the recorder couldn't capture very well. You can see it when options and exit are alternating even though only one of those is actually selected. I'm ignoring the result of

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find_if

. I control the menu selection using the keyboard exclusively (I disabled touch selection).

This second video is also from MSVC but only when I pass in the references directly rather than through the finger reference.




Источник: https://stackoverflow.com/questions/781 ... ith-window