Standard library header <cfloat>

This header was originally in the C standard library as <float.h>.

This header is part of the type support library, in particular it's part of the C numeric limits interface.

Macros

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)
(C++11)
 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)

Synopsis

#define FLT_ROUNDS /*see definition*/
#define FLT_EVAL_METHOD /*see definition*/
#define FLT_HAS_SUBNORM /*see definition*/
#define DBL_HAS_SUBNORM /*see definition*/
#define LDBL_HAS_SUBNORM /*see definition*/
#define FLT_RADIX /*see definition*/
#define FLT_MANT_DIG /*see definition*/
#define DBL_MANT_DIG /*see definition*/
#define LDBL_MANT_DIG /*see definition*/
#define FLT_DECIMAL_DIG /*see definition*/
#define DBL_DECIMAL_DIG /*see definition*/
#define LDBL_DECIMAL_DIG /*see definition*/
#define DECIMAL_DIG /*see definition*/
#define FLT_DIG /*see definition*/
#define DBL_DIG /*see definition*/
#define LDBL_DIG /*see definition*/
#define FLT_MIN_EXP /*see definition*/
#define DBL_MIN_EXP /*see definition*/
#define LDBL_MIN_EXP /*see definition*/
#define FLT_MIN_10_EXP /*see definition*/
#define DBL_MIN_10_EXP /*see definition*/
#define LDBL_MIN_10_EXP /*see definition*/
#define FLT_MAX_EXP /*see definition*/
#define DBL_MAX_EXP /*see definition*/
#define LDBL_MAX_EXP /*see definition*/
#define FLT_MAX_10_EXP /*see definition*/
#define DBL_MAX_10_EXP /*see definition*/
#define LDBL_MAX_10_EXP /*see definition*/
#define FLT_MAX /*see definition*/
#define DBL_MAX /*see definition*/
#define LDBL_MAX /*see definition*/
#define FLT_EPSILON /*see definition*/
#define DBL_EPSILON /*see definition*/
#define LDBL_EPSILON /*see definition*/
#define FLT_MIN /*see definition*/
#define DBL_MIN /*see definition*/
#define LDBL_MIN /*see definition*/
#define FLT_TRUE_MIN /*see definition*/
#define DBL_TRUE_MIN /*see definition*/
#define LDBL_TRUE_MIN /*see definition*/

© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
http://en.cppreference.com/w/cpp/header/cfloat