int memcmp_PF(const void *, uint_farptr_t, size_t) __ATTR_PURE__
The memcmp_PF() function compares the first len bytes of the memory areas s1 and flash s2. The comparision is performed using unsigned char operations. It is an equivalent of memcmp_P() function, except that it is capable working on all FLASH including the exteded area above 64kB.
The memcmp_PF() function returns an integer less than, equal to, or greater than zero if the first len bytes of s1 is found, respectively, to be less than, to match, or be greater than the first len bytes of s2.