strdiff(3)
locate first difference between two strings
SYNOPSIS
#include <publib.h>
size_t strdiff(const char *str1, const char *str2);
DESCRIPTION
strdiff finds the first character from the beginning that is
different in the two strings str1 and str2.
The terminating zero characters are considered different.
RETURN VALUE
strdiff returns a the offset of the first pair of differring
characters (or the offset of the first zero character it finds).