All data items are held in the native byte order of the AVR processor. The plain character type is signed by default. The floating-point types float and double are implemented as 32-bit and 64-bit IEEE floating-point.

Data Type Size in bytes Alignment in bytes

char

1

1

unsigned char

1

1

int

2

1

unsigned int

2

1

short

2

1

unsigned short

2

1

long

4

1

unsigned long

4

1

long long

8

1

unsigned long long

8

1

float

4

1

double (compiled with -msd)

4

1

double

8

1

long double

8

1

type * (pointer)

2

1

enum (enumeration)

2

1