Specifications

CAVR-4
142
Pointer types
AVR® IAR C/C++ Compiler
Reference Guide
CASTING
Casts between pointers have the following characteristics:
● Casting a value of an integer type to a pointer of a smaller type is performed by
truncation
● Casting a value of an integer type to a pointer of a larger type is performed by zero
extension
● Casting a pointer type to a smaller integer type is performed by truncation
● Casting a pointer type to a larger integer type is performed via casting to the largest
possible pointer that fits in the integer
● Casting a data pointer to a function pointer and vice versa is illegal
● Casting a function pointer to an integer type gives an undefined result.
size_t
size_t is the unsigned integer type required to hold the maximum size of an object.
The following table shows the typedef of size_t depending on the processor option:
__farflash 3 bytes Code signed int 0x0–0xFFFFFF
(16-bit arithmetics)
__hugeflash 3 bytes Code signed long 0x0–0xFFFFFF
__eeprom 1 byte EEPROM signed char 0x0–0xFF
__eeprom 2 bytes EEPROM signed int 0x0–0xFFFF
__generic 2 bytes
3 bytes
Data/Code signed int
signed long
The most significant bit (MSB)
determines whether __generic
points to CODE (1) or DATA (0). The
small generic pointer is generated
for the processor options -v0 and
-v1.
Generic processor option Typedef
-v0 and -v1 unsigned int
-v2, -v3, -v4, -v5, and -v6 unsigned long
Table 35: size_t typedef
Keyword Pointer size Memory space Index type Range
Table 34: Data pointers