c++ - C++是否保证参数评估的原子性？

Question

int a()
{
    return 1;
}

int b()
{
    return 2;
}

int c()
{
    return 3;
}

int g(int, int)
{
    return 0;
}

void f(int, int)
{}

int main()
{
    f(g(a(), b()),
      c());
}

我知道根据C++标准，未指定函数参数的求值顺序。

换句话说，实际评估顺序可能是:

a(), b(), c()

c(), a(), b()

b(), a(), c()

c(), b(), a()

我只是好奇:

C++ stardard是否保证c()和a()之间永远不会调用b()？

Answer 1

我想从C++ 17开始就可以保证。 N4659(2017年3月，科纳后工作草案/ C++ 17 DIS)[intro.execution] / 18，reads:

For each function invocation F, for every evaluation A that occurs within F and every evaluation B that does not occur within F but is evaluated on the same thread and as part of the same signal handler (if any), either A is sequenced before B or B is sequenced before A. In other words, function executions do not interleave with each other.

在C++ 17之前，我们没有这样的保证。