Hi, Committed with a minor modification: /* * Return a pointer to the first occurrence of needle in haystack. */ char *dStr_memmem(Dstr *haystack, Dstr *needle) { int i; if (needle && haystack) { if (needle->len == 0) return haystack->str; for (i = 0; i <= (haystack->len - needle->len); i++) { - if (!memcmp(haystack->str + i, needle->str, needle->len)) + if (haystack->str[i] == needle->str[0] && + !memcmp(haystack->str + i, needle->str, needle->len)) return haystack->str + i; } } return NULL; } The idea is to avoid a 3 parameters function call per each checked character. Maybe it's even better to implement it without a function call (like dStristr()), but I haven't done any profiling so I'm not sure. It looks like an improvement though. ;-) -- Cheers Jorge.-