What is a ‘binary-safe’ string?

What do people mean when they say “binary-safe strings”? In C, strings are traditionally represented as a pointer to bytes, i.e. char*, where the array of bytes is terminated by a “null byte” (i.e. '\0', i.e. 0). This representation has the disadvantage that your string of bytes cannot itself contain a null byte, and so this structure cannot represent arbitrary strings of bytes. That is, C-strings are not “binary-safe”.

Binary-safe strings in C are typically implemented with an explicit known length. Something like:

struct bytestring {
  size_t len;
  unsigned char * bytes;
};

I wrote this because I felt like it. This post is my own, and not associated with my employer.