Plan 9 from Bell Labs’s /usr/web/sources/patch/applied/ape-memchr/memchr.c
#include <string.h> void* memchr(const void *ap, int c, size_t n) { unsigned char *sp; sp = ap; c &= 0xFF; while(n > 0) { if(*sp++ == c) return sp-1; n--; } return 0; }