Handling "Thrown exception type is not nothrow copy constructible" Warning

Question

Going back to C++ development after a 12 years hiatus. I'm using JetBrains's CLion software which is great since it provides a lot of input on possible issues on my class design. One of the warning I get in my class' constructor throw statement is: Thrown exception type is not nothrow copy constructible. Here is a code sample that generates this warning:

#include <exception>
#include <iostream>

using std::invalid_argument;
using std::string;

class MyClass {
    public:
        explicit MyClass(string value) throw (invalid_argument);
    private:
        string value;
};

MyClass::MyClass(string value) throw (invalid_argument) {
    if (value.length() == 0) {
        throw invalid_argument("YOLO!"); // Warning is here.
    }

    this->value = value;
}

This piece of code compiles and I am able to unit test it. But I would like very much to get rid of this warning (in order to understand what I am doing wrong, even though it compiles).

Why are you using throw specifications? They have been deprecated. https://stackoverflow.com/questions/13841559/deprecated-throw-list-in-c11 — , Oct 11 '17 at 21:31
Pain `throw` specifiers bring. Much pain. Better off without, you are. — user4581301, Oct 11 '17 at 22:04
Regardless of the interaction between nothrow copy and exceptions (which I am not expert in), note that the error you are trying to detect is not something that should be handled with an exception. it is basically a usage or logical mistake, you should terminate your program (or detect empty strings are compile time) if you don’t want empty strings as constructor input. — alfC, Aug 16 '21 at 06:28

score 10 · Answer 1 · edited Apr 25 '18 at 09:40

The comment provided by Neil is valid. In C++ 11, using throw in a function signature has been deprecated in favor of noexcept. In this case, my constructor's signature should have been:

explicit MyClass(string value) noexcept(false);

But, since noexcept(false) is applied by default to all functions, unless noexcept or noexcept(true) is specified, I can simply use:

explicit MyClass(string value);

Going back to how to fix the "Thrown exception type is not nothrow copy constructible” warning, I found this post that explains very well what the issue is and how to fix it.

Handling "Thrown exception type is not nothrow copy constructible" Warning

1 Answers1

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