Node:Range of Type, Next:, Previous:Width of Type, Up:Data Type Measurements


Range of an Integer Type

Suppose you need to store an integer value which can range from zero to one million. Which is the smallest type you can use? There is no general rule; it depends on the C compiler and target machine. You can use the MIN and MAX macros in limits.h to determine which type will work.

Each signed integer type has a pair of macros which give the smallest and largest values that it can hold. Each unsigned integer type has one such macro, for the maximum value; the minimum value is, of course, zero.

The values of these macros are all integer constant expressions. The MAX and MIN macros for char and short int types have values of type int. The MAX and MIN macros for the other types have values of the same type described by the macro--thus, ULONG_MAX has type unsigned long int.

SCHAR_MIN
This is the minimum value that can be represented by a signed char.
SCHAR_MAX
UCHAR_MAX
These are the maximum values that can be represented by a signed char and unsigned char, respectively.
CHAR_MIN
This is the minimum value that can be represented by a char. It's equal to SCHAR_MIN if char is signed, or zero otherwise.
CHAR_MAX
This is the maximum value that can be represented by a char. It's equal to SCHAR_MAX if char is signed, or UCHAR_MAX otherwise.
SHRT_MIN
This is the minimum value that can be represented by a signed short int. On most machines that the GNU C library runs on, short integers are 16-bit quantities.
SHRT_MAX
USHRT_MAX
These are the maximum values that can be represented by a signed short int and unsigned short int, respectively.
INT_MIN
This is the minimum value that can be represented by a signed int. On most machines that the GNU C system runs on, an int is a 32-bit quantity.
INT_MAX
UINT_MAX
These are the maximum values that can be represented by, respectively, the type signed int and the type unsigned int.
LONG_MIN
This is the minimum value that can be represented by a signed long int. On most machines that the GNU C system runs on, long integers are 32-bit quantities, the same size as int.
LONG_MAX
ULONG_MAX
These are the maximum values that can be represented by a signed long int and unsigned long int, respectively.
LONG_LONG_MIN
This is the minimum value that can be represented by a signed long long int. On most machines that the GNU C system runs on, long long integers are 64-bit quantities.
LONG_LONG_MAX
ULONG_LONG_MAX
These are the maximum values that can be represented by a signed long long int and unsigned long long int, respectively.
WCHAR_MAX
This is the maximum value that can be represented by a wchar_t. See Extended Char Intro.

The header file limits.h also defines some additional constants that parameterize various operating system and file system limits. These constants are described in System Configuration.