为什么std :: string不提供转换为const char *？ [英] Why does std::string not provide a conversion to const char*?

问题描述

这更像是一个政策或历史问题。为什么决定不会为std :: string提供const char *转换？有恐惧有人可能做printf（％s，s），并相信它会自动转换？对这个问题是否有任何公开讨论？

This is more of a policy or a historical question. Why was it decided not to provide a const char * conversion for std::string? Were there a fear someone might do printf("%s", s) and believe it would automatically convert? Are there any open discussions on this issue?

推荐答案

自动投射几乎总是邪恶的。如果有一个转换 const char * ，一个 std :: string 也可以自动转换为其他指针类型并可能导致很难找到错误。有 c_str（）方法返回 const char * ，所以你仍然可以实现你需要的。此外，类型转换在逻辑上是不正确的 - std :: string 不等同于 const char * 。

Automatic casts are almost always evil. If there were a cast to const char *, a std::string could be also automatically cast to other pointer types and that could lead to hard to find bugs. There is the c_str() method that returns const char * so you can still achieve what you need. Also, the typecast is not logically correct - std::string is not equivalent to const char *.

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