uint16_unpack man page
uint16_unpack — read an unsigned little-endian 16-bit integer
void uint16_unpack(const char s,uint16 *u);
uint16 is a 16-bit unsigned integer type, normally either unsigned int or unsigned long.
uint16_unpack portably reads a uint16 as stored on a little-endian architecture from s and writes it into u in the native byte order.
uint16_pack(3), uint16_read(3), uint16_read_big(3), uint16_unpack_big(3).