uint16_unpack_big man page
uint16_unpack_big — read an unsigned big-endian 16-bit integer
void uint16_unpack_big(const char s,uint16 *u);
uint16 is a 16-bit unsigned integer type, normally either unsigned int or unsigned long.
uint16_unpack_big portably reads a uint16 as stored on a big-endian architecture (i.e. in network byte order) from s and writes it into u in the native byte order.
uint16_pack_big(3), uint16_read(3), uint16_read_big(3), uint16_unpack(3).