man byte_rchr () - search for a byte in a string
NAME
byte_rchr - search for a byte in a string
SYNTAX
#include <byte.h>
long byte_rchr(const char *haystack,unsigned long len,char needle);
DESCRIPTION
byte_chr returns the largest integer i between 0 and len-1 inclusive such that one[i] equals needle.
If no such integer exists, byte_chr returns len.
byte_rchr may read all bytes one[0], one[1], ..., one[len-1], even if not all the bytes are relevant to the answer.