Dear boosters Here is my review of fixed_string

- What is your evaluation of the design?

I have just completed a similar but much less ambitious design - about 700 LOC in total. The purpose is to replace char string[N] representing string in an ageing code base that is C++98 currently and partly embedded. My design does support a partial compatibility with std::string but that was not the primary goal. The interface compatibility of std::string is a nice feature, but I do not see a reason to attempt to make it a drop-in replacement. The non-compatibility with char[N] is missed by me and probably also some other in the embedded domain. It would be nice if fixed_string<N> had size = N + 1 for char types.

- What is your evaluation of the implementation?

Nice and clean. As others have noted, constexpr and noexcept support would be nice. I would also prefer if I could have an option that does not require usage of exceptions, perhaps as a configuration option. Specifically, I would like to be able to control error handling (terminate instead of throw, ability to react to undefined behaviour). Also, I would like to have more forgiving functions that could return the status of failing operations.

- What is your evaluation of the documentation?

Nice and clean.

- What is your evaluation of the potential usefulness of the library?

If the interface could be extended, It could potentially be useful to many - and to me - if I manage to convince my company to ugrade to C++17. So to summarize: 1) compatibility with char[N]: this requires that the size member is removed. In my source, I still have an O(1) size implemented by having data[N] give the free space in the string. If data[N] == 255, this indicates that the real free size is stored in the elements data[N - 1] and below. There are many ways to encode that length portably. 2) append and assign could have companion functions, that behave in spirit like strncpy/strncat. I have named these function try_append and try_assign. 3) Errorhandling strategy available.

- Did you try to use the library? With what compiler? Did you have any problems?

No, just reading code.

- How much effort did you put into your evaluation? A glance? A quick reading? In-depth study?

About three hours reading and writing this comment.

- Are you knowledgeable about the problem domain?

Yes.

And finally, every review should answer this question: - Do you think the library should be accepted as a Boost library?

The constexpr and noexcept parts should be fixed and compatibility with char[] would be nice. But yes, it should be accepted.