Dear All, Considering small-capacity fixed_strings like the example that I gave previously: struct NameAndAddress { static_string<14> firstname; static_string<14> surname; static_string<30> address_line_1; static_string<22> city; static_string<10> postcode; }; I have been looking at how best to copy and compare them. For small-capacity strings, and also for large-capacity strings when their size approaches the capacity, it will be quicker to unconditionally copy/compare everything, including the unused bytes beyond the end, rather than looping over just the current size. I've tried a very crude benchmark based on this: struct string { uint8_t size; std::array<char,N> data; }; extern void copy_all(string& dest, const string& src) { dest = src; } extern void copy_size(string& dest, const string& src) { dest.size = src.size; std::copy(src.data.begin(), src.data.begin()+src.size, dest.data.begin()); } Results will depend on the architecture but I found that for N < 64 it was probably always best to copy_all(). For N==255, time for copy_all() and copy_size() is about equal when the container is half full. Things are more complicated for operator== because of the unused bytes. It would be necessary to initialise everything to 0 and maintain that during e.g. erase() and assign(). I haven't tried to benchmark that but I suspect the trade-off would be similar. operator< is a mess due to endianness. I don't know whether any compilers or memcmp() implementations are smart enough to use byte-swap instructions to process data 4 or 8 bytes at a time. I don't think I'm suggesting that this should necessarily be implemented in fixed_string, at least not without lots more investigation, but it does illustrate more of the trade-offs that exist between different applications. Regards, Phil.