char * strncat_PF(char *dest, uint_farptr_t src, size_t len)
The strncat_PF() function is similar to strncat(), except that the src string must be located in program space (flash) and is addressed using a far pointer.
The strncat_PF() function returns a pointer to the resulting string dst. The contents of RAMPZ SFR are undefined when the function returns.