c++ - 为什么我不必从std :: string的c_str函数中释放字符串？(Why I don’t have to free string from c_str function of std::string?)

Question

Why I don't have to free string from c_str function of std::string?

(为什么我不必从std :: string的c_str函数中释放字符串？)

How the function generate const char* and how it be destroyed?

(函数如何生成const char *以及如何销毁它？)

  ask by leejun translate from so

Answer 1

The const char* return from c_str() is managed by the std::string itself, and is destroyed when the std::string goes out of date.

(从c_str()返回的const char*由std::string本身管理，并在std::string过时时销毁。)

In this regard, one must be careful they don't attempt to use the pointer returned from c_str() after the std::string is destroyed:

(在这方面，必须小心，不要在销毁std::string之后尝试使用从c_str()返回的指针：)

const char* getName()
{
    std::string name = "Joe";
    return name.c_str();
}

The above is wrong, because when name is destructed as getName returns, the pointer will become invalid.

(上面的说法是错误的，因为当name随getName返回而被破坏时，指针将变为无效。)