typedef union {
unsigned int DW;
struct {
unsigned char byte0;
unsigned char byte1;
unsigned char byte2;
unsigned char byte3;
} DWB;
} DWORD_BYTE;
DWORD_BYTE byte_in_dword;
byte_in_dword.DWB.byte0 = 0x00;
byte_in_dword.DWB.byte1 = 0x00;
byte_in_dword.DWB.byte3 = 0x00;
byte_in_dword.DWB.byte3 = 0x00;