C numeric limits interface

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C numeric limits interface
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See also std::numeric_limits interface.

Defined in header <cstdint>
PTRDIFF_MIN
(C++11)
minimum value of object of std::ptrdiff_t type
(macro constant)
PTRDIFF_MAX
(C++11)
maximum value of object of std::ptrdiff_t type
(macro constant)
SIZE_MAX
(C++11)
maximum value of object of std::size_t type
(macro constant)
SIG_ATOMIC_MIN
(C++11)
minimum value of object of std::sig_atomic_t type
(macro constant)
SIG_ATOMIC_MAX
(C++11)
maximum value of object of std::sig_atomic_t type
(macro constant)
WCHAR_MIN
(C++11)
minimum value of object of wchar_t type
(macro constant)
WCHAR_MAX
(C++11)
maximum value of object of wchar_t type
(macro constant)
WINT_MIN
(C++11)
minimum value of object of std::wint_t type
(macro constant)
WINT_MAX
(C++11)
maximum value of object of std::wint_t type
(macro constant)

Limits of integer types

Defined in header <climits>
CHAR_BIT
number of bits in a byte
(macro constant)
MB_LEN_MAX
maximum number of bytes in a multibyte character
(macro constant)
CHAR_MIN
minimum value of char
(macro constant)
CHAR_MAX
maximum value of char
(macro constant)
SCHAR_MINSHRT_MININT_MINLONG_MINLLONG_MIN
(C++11)
minimum value of signed char, short, int, long and long long respectively
(macro constant)
SCHAR_MAXSHRT_MAXINT_MAXLONG_MAXLLONG_MAX
(C++11)
maximum value of signed char, short, int, long and long long respectively
(macro constant)
UCHAR_MAXUSHRT_MAXUINT_MAXULONG_MAXULLONG_MAX
(C++11)
maximum value of unsigned char, unsigned short, unsigned int,
unsigned long and unsigned long long respectively
(macro constant)

Note: the types of these constants, other than CHAR_BIT and MB_LEN_MAX, are required to match the results of the integral promotions as applied to objects of the types they describe: CHAR_MAX may have type int or unsigned int, but never char. Similarly USHRT_MAX may not be of an unsigned type: its type may be int.

Limits of floating point types

Defined in header <cfloat>
FLT_RADIX
the radix (integer base) used by the representation of all three floating-point types
(macro constant)
DECIMAL_DIG
(C++11)
conversion from long double to decimal with at least DECIMAL_DIG digits and back to long double is the identity conversion. : this is the decimal precision required to serialize/deserialize a long double (see also std::numeric_limits::max_digits10)
(macro constant)
FLT_DECIMAL_DIGDBL_DECIMAL_DIGLDBL_DECIMAL_DIG
(C++17)
conversion from float/double/long double to decimal with at least FLT_DECIMAL_DIG/DBL_DECIMAL_DIG/LDBL_DECIMAL_DIG digits and back is the identity conversion. : this is the decimal precision required to serialize/deserialize a floating-point value (see also std::numeric_limits::max_digits10). Defined to at least 6, 10, and 10 respectively, or 9 for IEEE float and 17 for IEEE double.
(macro constant)
FLT_MINDBL_MINLDBL_MIN
minimum normalized positive value of float, double and long double respectively
(macro constant)
FLT_TRUE_MINDBL_TRUE_MINLDBL_TRUE_MIN
(C++17)
minimum positive value of float, double and long double respectively
(macro constant)
FLT_MAXDBL_MAXLDBL_MAX
maximum value of float, double and long double respectively
(macro constant)
FLT_EPSILONDBL_EPSILONLDBL_EPSILON
difference between 1.0 and the next representable value for float, double and long double respectively
(macro constant)
FLT_DIGDBL_DIGLDBL_DIG
number of decimal digits that are guaranteed to be preserved in text -> float/double/long double -> text roundtrip without change due to rounding or overflow (see std::numeric_limits::digits10 for explanation)
(macro constant)
FLT_MANT_DIGDBL_MANT_DIGLDBL_MANT_DIG
number of base FLT_RADIX digits that can be represented without losing precision for float, double and long double respectively
(macro constant)
FLT_MIN_EXPDBL_MIN_EXPLDBL_MIN_EXP
minimum negative integer such that FLT_RADIX raised by power one less than that integer is a normalized float, double and long double respectively
(macro constant)
FLT_MIN_10_EXPDBL_MIN_10_EXPLDBL_MIN_10_EXP
minimum negative integer such that 10 raised by power one less than that integer is a normalized float, double and long double respectively
(macro constant)
FLT_MAX_EXPDBL_MAX_EXPLDBL_MAX_EXP
maximum positive integer such that FLT_RADIX raised by power one more than that integer is a normalized float, double and long double respectively
(macro constant)
FLT_MAX_10_EXPDBL_MAX_10_EXPLDBL_MAX_10_EXP
maximum positive integer such that 10 raised by power one more than that integer is a normalized float, double and long double respectively
(macro constant)
default rounding mode of floating-point arithmetics
(macro constant)
specifies in what precision all arithmetic operations are done
(macro constant)
FLT_HAS_SUBNORMDBL_HAS_SUBNORMLDBL_HAS_SUBNORM
(C++17)
specifies whether the type supports subnormal (denormal) numbers: -1 indeterminable, 0 absent, 1 present
(macro constant)

See also