11 calculate a simple checksum
13 static unsigned sccs_checksum(const unsigned char *buf, size_t len)
23 static void *map_file(const char *fname, size_t *size)
25 int fd = open(fname, O_RDONLY);
30 p = mmap(0, st.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
38 int main(int argc, const char *argv[])
42 const char *fname = argv[1];
45 buf = map_file(fname, &size);
47 sum = sccs_checksum(buf, size);
49 printf("%05u\n", sum);