Appropriate tangent: Remember that part where null terminated strings save at most three-bytes per string? And if the allocator is long word aligned it saves none-bytes. The first to arrive sets a disproportionate amount of the direction.

Not sure how you get that. Let's assume that memory is allocated in sizes that are multiples of 4, and length-prefixed strings have a 4 byte length prefix.

  str len:    c-str bytes:    size-prefix bytes:  difference:
  1           1+1 (4)         4+1 (8)             4
  2           2+1 (4)         4+2 (8)             4
  3           3+1 (4)         4+3 (8)             4
  4           4+1 (8)         4+4 (8)             0
  5           5+1 (8)         4+5 (12)            4
  6           6+1 (8)         4+6 (12)            4
  7           7+1 (8)         4+7 (12)            4
  8           8+1 (12)        4+8 (12)            0

So, for example: "ABCDE" as a C-style string would require 5 bytes for the string plus one for the null terminator, which would be satisfied by an allocation of 8 bytes. An equivalent length-prefixed string would require 4 bytes for the prefix plus 5 for the string, which would then be rounded up to 12.

The only time the size-prefixed variant doesn't require more memory is when the string length is a multiple of 4. So the length-prefixed version requires an additional 3 bytes on average.

Meanwhile this extra memory usage _might_ be relevant on an 8k microcontroller, but even that is questionable given such an application is likely not storing many strings. And the time (and battery! and sanity!) saved by not performing strlen type operations.

Worth every byte.

Thanks for the clarification, but I believe neither has said anything in error (replace most with average). I wonder what the breakdown of string lengths in say, clang or nginx is?