strlist_string
const char *descr = strlist_string(buf, sllen, i);
return strlist_string(names, len, index);
assert(strcmp(strlist_string(sl, slsize, 0), "zero") == 0);
assert(strcmp(strlist_string(sl, slsize, 1), "one") == 0);
assert(strcmp(strlist_string(sl, slsize, 2), "two") == 0);
assert(strcmp(strlist_string(sl, slsize, 3), "three") == 0);
assert(strcmp(strlist_string(sl, slsize, 4), "four") == 0);
assert(strcmp(strlist_string(sl, slsize, 5), "five") == 0);
assert(strlist_string(sl, slsize, 6) == NULL);
assert(strcmp(strlist_string(sl, slsize, 0), "zero") == 0);
assert(strcmp(strlist_string(sl, slsize, 1), "") == 0);
assert(strcmp(strlist_string(sl, slsize, 2), "two") == 0);
assert(strcmp(strlist_string(sl, slsize, 3), "") == 0);
assert(strcmp(strlist_string(sl, slsize, 4), "four") == 0);
assert(strcmp(strlist_string(sl, slsize, 5), "") == 0);
assert(strcmp(strlist_string(sl, slsize, 6), "") == 0);
assert(strlist_string(sl, slsize, 7) == NULL);
assert(strcmp(strlist_string(newsl, newslsize, 0), "zero") == 0);
assert(strcmp(strlist_string(newsl, newslsize, 1), "one") == 0);
assert(strcmp(strlist_string(newsl, newslsize, 2), "two") == 0);
assert(strcmp(strlist_string(newsl, newslsize, 3), "three") == 0);
assert(strcmp(strlist_string(newsl, newslsize, 4), "four") == 0);
assert(strcmp(strlist_string(newsl, newslsize, 5), "five") == 0);
assert(strlist_string(newsl, newslsize, 6) == NULL);
const char * strlist_string(const char *, size_t, unsigned int);