const void memrchr_P(const void *, int __val, size_t __len)
The memrchr_P() function is like the memchr_P() function, except that it searches backwards from the end of the len bytes pointed to by src instead of forwards from the front. (Glibc, GNU extension.)
The memrchr_P() function returns a pointer to the matching byte or NULL if the character does not occur in the given memory area.