为什么带引号的字符串在 std::string 之前匹配 bool 方法签名? [英] Why does a quoted string match bool method signature before a std::string?

问题描述

给定以下方法:

// Method 1
void add(const std::string& header, bool replace);

//Method 2
void add(const std::string& name, const std::string& value);

看起来下面的代码最终会调用方法 1 而不是方法 2:

It would appear that the following code will end up calling method 1 instead of method 2:

something.add("Hello", "World");

我最终创建了另一个如下所示的方法:

I ended up creating another method that looks like this:

//Method 3
void MyClass::add(const char* name, const char* value) {
    add(std::string(name), std::string(value));
}

它奏效了.因此，当一个方法接受一个带引号的字符串"时，它似乎会按以下顺序匹配:

It worked. So it would seem that when a method accepts a "quoted string" it will match in the following order:

1. const char*
2. bool
3. std::string

为什么在 std::string 之前将带引号的字符串视为 bool ?这是通常的行为吗?我为这个项目编写了大量代码，并且没有遇到任何其他问题，因为选择了错误的方法签名......

Why would a quoted string be treated as a bool before a std::string? Is this the usual behavior? I have written a decent amount of code for this project and haven't had any other issues with the wrong method signature being selected...

推荐答案

我的猜测是从指针到 bool 的转换是一种隐式原始类型转换，其中转换为 std::string 需要构造函数的调用和临时的构造.

My guess is the conversion from pointer to bool is an implicit primitive type conversion, where the conversion to std::string requires the call of a constructor and the construction of a temporary.

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