Plan 9 from Bell Labs’s /usr/web/sources/contrib/anothy/src/lib/djb-ape/byte/str_len.c
#include "str.h" unsigned int str_len(const char *s) { register const char *t; t = s; for (;;) { if (!*t) return t - s; ++t; if (!*t) return t - s; ++t; if (!*t) return t - s; ++t; if (!*t) return t - s; ++t; } }