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Data type constants

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Data type constants are implementation-dependent ranges of values allowed for integral and floating-point data types.

Integral type constants

These constants give the ranges for the integral data types. To use these constants, include the limits.h header in your source file:

#include <limits.h>

Note

The /J compiler option changes the default char type from signed char to unsigned char.

Constant Value Description
CHAR_BIT 8 Number of bits in a char
SCHAR_MIN (-128) Minimum signed char value
SCHAR_MAX 127 Maximum signed char value
UCHAR_MAX 255 (0xff) Maximum unsigned char value
CHAR_MIN (-128) (0 if /J option used) Minimum char value
CHAR_MAX 127 (255 if /J option used) Maximum char value
MB_LEN_MAX 5 Maximum number of bytes in multibyte char
SHRT_MIN -32768 Minimum signed short value
SHRT_MAX 32767 Maximum signed short value
USHRT_MAX 65535 (0xffff) Maximum unsigned short value
INT_MIN (-2147483647 - 1) Minimum signed int value
INT_MAX 2147483647 Maximum signed int value
UINT_MAX 4294967295 (0xffffffff) Maximum unsigned int value
LONG_MIN (-2147483647L - 1) Minimum signed long value
LONG_MAX 2147483647L Maximum signed long value
ULONG_MAX 4294967295UL (0xfffffffful) Maximum unsigned long value
LLONG_MIN (-9223372036854775807LL - 1) Minimum signed long long or __int64 value
LLONG_MAX 9223372036854775807LL Maximum signed long long or __int64 value
ULLONG_MAX 0xffffffffffffffffull Maximum unsigned long long value
_I8_MIN (-127i8 - 1) Minimum signed 8-bit value
_I8_MAX 127i8 Maximum signed 8-bit value
_UI8_MAX 0xffui8 Maximum unsigned 8-bit value
_I16_MIN (-32767i16 - 1) Minimum signed 16-bit value
_I16_MAX 32767i16 Maximum signed 16-bit value
_UI16_MAX 0xffffui16 Maximum unsigned 16-bit value
_I32_MIN (-2147483647i32 - 1) Minimum signed 32-bit value
_I32_MAX 2147483647i32 Maximum signed 32-bit value
_UI32_MAX 0xffffffffui32 Maximum unsigned 32-bit value
_I64_MIN (-9223372036854775807 - 1) Minimum signed 64-bit value
_I64_MAX 9223372036854775807 Maximum signed 64-bit value
_UI64_MAX 0xffffffffffffffffui64 Maximum unsigned 64-bit value
_I128_MIN (-170141183460469231731687303715884105727i128 - 1) Minimum signed 128-bit value
_I128_MAX 170141183460469231731687303715884105727i128 Maximum signed 128-bit value
_UI128_MAX 0xffffffffffffffffffffffffffffffffui128 Maximum unsigned 128-bit value
SIZE_MAX same as _UI64_MAX if _WIN64 is defined, or UINT_MAX Maximum native integer size
RSIZE_MAX same as (SIZE_MAX >> 1) Maximum secure library integer size

Floating-point type constants

The following constants give the range and other characteristics of the long double, double and float data types. To use these constants, include the float.h header in your source file:

#include <float.h>
Constant Value Description
DBL_DECIMAL_DIG 17 # of decimal digits of rounding precision
DBL_DIG 15 # of decimal digits of precision
DBL_EPSILON 2.2204460492503131e-016 Smallest such that 1.0 + DBL_EPSILON != 1.0
DBL_HAS_SUBNORM 1 Type supports subnormal (denormal) numbers
DBL_MANT_DIG 53 # of bits in significand (mantissa)
DBL_MAX 1.7976931348623158e+308 Maximum value
DBL_MAX_10_EXP 308 Maximum decimal exponent
DBL_MAX_EXP 1024 Maximum binary exponent
DBL_MIN 2.2250738585072014e-308 Minimum normalized positive value
DBL_MIN_10_EXP (-307) Minimum decimal exponent
DBL_MIN_EXP (-1021) Minimum binary exponent
_DBL_RADIX 2 Exponent radix
DBL_TRUE_MIN 4.9406564584124654e-324 Minimum positive subnormal value
FLT_DECIMAL_DIG 9 Number of decimal digits of rounding precision
FLT_DIG 6 Number of decimal digits of precision
FLT_EPSILON 1.192092896e-07F Smallest such that 1.0 + FLT_EPSILON != 1.0
FLT_HAS_SUBNORM 1 Type supports subnormal (denormal) numbers
FLT_MANT_DIG 24 Number of bits in significand (mantissa)
FLT_MAX 3.402823466e+38F Maximum value
FLT_MAX_10_EXP 38 Maximum decimal exponent
FLT_MAX_EXP 128 Maximum binary exponent
FLT_MIN 1.175494351e-38F Minimum normalized positive value
FLT_MIN_10_EXP (-37) Minimum decimal exponent
FLT_MIN_EXP (-125) Minimum binary exponent
FLT_RADIX 2 Exponent radix
FLT_TRUE_MIN 1.401298464e-45F Minimum positive subnormal value
LDBL_DIG 15 # of decimal digits of precision
LDBL_EPSILON 2.2204460492503131e-016 Smallest such that 1.0 + LDBL_EPSILON != 1.0
LDBL_HAS_SUBNORM 1 Type supports subnormal (denormal) numbers
LDBL_MANT_DIG 53 # of bits in significand (mantissa)
LDBL_MAX 1.7976931348623158e+308 Maximum value
LDBL_MAX_10_EXP 308 Maximum decimal exponent
LDBL_MAX_EXP 1024 Maximum binary exponent
LDBL_MIN 2.2250738585072014e-308 Minimum normalized positive value
LDBL_MIN_10_EXP (-307) Minimum decimal exponent
LDBL_MIN_EXP (-1021) Minimum binary exponent
_LDBL_RADIX 2 Exponent radix
LDBL_TRUE_MIN 4.9406564584124654e-324 Minimum positive subnormal value
DECIMAL_DIG same as DBL_DECIMAL_DIG Default (double) decimal digits of rounding precision

See also

Global constants