Plan 9 from Bell Labs’s /usr/web/sources/contrib/anothy/src/lib/djb-ape/byte/fmt_str.c
#include "fmt.h" unsigned int fmt_str(register char* s,register const char* t) { register unsigned int len; char ch; len = 0; if (s) { while (ch = t[len]) s[len++] = ch; } else while (t[len]) len++; return len; }