Endianness defines the order in which bytes that represent large numerical values are stored in memory.

There are two types of endianness:

• Big-endian: The most significant byte is stored first. A 32-bit value, 0x01020304, is stored at the ptr address, as follows: 
  
  

  Offset in memory (byte)	Value
  ptr	0x01
  ptr + 1	0x02
  ptr + 2	ox03
  ptr + 3	0x04

  
  Examples of big-endian architectures include AVR32 and Motorola 68000.

• Little-endian: The least significant byte is stored first. A 32-bit value, 0x01020304, is stored at the ptr address, as follows:
  
  

  Offset in memory (byte)	Value
  ptr	0x04
  ptr + 1	0x03
  ptr + 2	0x02
  ptr + 3	0x01

  
  The x86 architecture is little-endian.

Taking care of endianness is especially essential when exchanging data with other systems. If a developer sends a 32-bit integer, say, 0x01020304, as it is, it may be read as 0x04030201 if the endianness of the receiver does not match the endianness of the sender. That is why data should be serialized.

In this recipe, we will learn how to determine the endianness of our target system.