char *str_cat (char*, size_t, const char*);
char *str_ncat (char*, size_t, const char*, size_t);
int str_cmp (const char*, const char*);
char *str_cat (char*, size_t, const char*);
char *str_ncat (char*, size_t, const char*, size_t);
int str_cmp (const char*, const char*);