是否可以将va_list传递给可变参数模板？ [英] Is it possible to pass va_list to variadic template?

问题描述

我知道 va_list 通常是您应该避免的事情，因为它不太安全，但是可以通过类似这样的函数传递参数：

I know that va_list is usually something you should avoid since its not very safe, but is it possible to pass the arguments from a function like:

void foo(...);

到类似

template<typename... Args>
void bar(Args... arguments);

？

编辑：最初我想要尝试使用它来调用具有可变数量的参数/类型的虚函数，但这并不是使该问题变得无关紧要的方法。最终我最终做了这样的事情：

edit: Originally I wanted to try to use this to call a virtual function with a variable amount of arguments / types, but this was not the way to go making this question kind of irrelevant. Eventually I ended up doing something like this:

struct ArgsPackBase
{
    virtual ~ArgsPackBase() {}
};

template<typename... Args>
struct ArgsPack : public ArgsPackBase
{
public:
    ArgsPack(Args... args_)
        : argsTuple(args_...)
    {}

    void call(std::function<void(Args...)> function)
    {
        callExpansion(function, std::index_sequence_for<Args...>{});
    }

private:
    template<std::size_t... I>
    void callExpansion(std::function<void(Args...)> function, std::index_sequence<I...>)
    {
        function(std::get<I>(argsTuple)...);
    }

    std::tuple<Args...> argsTuple;
};

推荐答案

不，可变参数函数是运行时功能，并且您传递给可变参数模板的参数数量（尽管是变量）必须在编译时知道。

No, variadic function arguments are a runtime feature, and the number of arguments you pass to a variadic template, although variable, must be known at the compile time.

这篇关于是否可以将va_list传递给可变参数模板？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！