C ++ 64位int：按引用传递或按值传递 [英] C++ 64 bit int: pass by reference or pass by value

问题描述

这是关于64位整数的效率问题。假设我不需要修改 int参数的值，那么我应该通过值或引用传递它。

This is an efficiency question about 64 bit ints. Assuming I don't need to modify the value of a "int" parameter, should I pass it by value or reference.

假设使用32位计算机：

Assuming 32 bit machine:

1）32位整数：我猜测答案是按值传递，因为按引用传递会产生额外的内存查找开销。

1) 32 bit int: I guess the answer is "pass by value" as "pass by reference" will have overhead of extra memory lookup.

2）64位int：如果我通过引用传递，我仅在堆栈上传递32位地址，但需要额外的内存查找。那么其中哪一个更好（参考或值）呢？

2) 64 bit int: If I pass by reference, I only pass 32 bit address on the stack, but need an extra memory lookup. So which one of them is better (reference or value)?

如果机器是64位呢？

问候

JP

推荐答案

按值传递-肯定是。如果系统是64位的，则意味着它非常快速地复制了64位字。

Pass by value - definitely. If the system is 64-bit it means it copies 64-bit word extremely fast.

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