将字符串转换为矢量时，字符串迭代器不兼容的错误<byte>

Question

I have Const variable :

#define     ERROR_ME        std::string("Error Message")

in the function, I want return std::vector so, I write this:

return std::vector<byte>(ERROR_ME.begin(), ERROR_ME.end()); // this have error

can you help me?

Answer 1

No you don't have a "Const [sic] variable", you have a symbolic constant that is replaced in the source before the compiler proper gets a chance to read it.

The code the compiler will see is not

return std::vector<byte>(ERROR_ME.begin(), ERROR_ME.end());

but instead

return std::vector<byte>(std::string("Error Message").begin(), std::string("Error Message").end());

That is, you get the begin and end iterators from two different and unrelated objects. Comparing or other interacting of unrelated iterators leads to undefined behavior .

If you want a true constant then use eg

std::string const ERROR_ME = "Error Message";