Standard library header <cfloat>
From cppreference.com
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_DIG
DBL_DECIMAL_DIG
LDBL_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_MIN
DBL_MIN
LDBL_MIN
|
minimum normalized positive value of
float
,
double
and
long
double
respectively
(macro constant) |
|
FLT_TRUE_MIN
DBL_TRUE_MIN
LDBL_TRUE_MIN
(C++17)
|
minimum positive value of
float
,
double
and
long
double
respectively
(macro constant) |
|
FLT_MAX
DBL_MAX
LDBL_MAX
|
maximum finite value of
float
,
double
and
long
double
respectively
(macro constant) |
|
FLT_EPSILON
DBL_EPSILON
LDBL_EPSILON
|
difference between
1.0
and the next representable value for
float
,
double
and
long
double
respectively
(macro constant) |
|
FLT_DIG
DBL_DIG
LDBL_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_DIG
DBL_MANT_DIG
LDBL_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_EXP
DBL_MIN_EXP
LDBL_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_EXP
DBL_MIN_10_EXP
LDBL_MIN_10_EXP
|
minimum negative integer such that
10
raised to that power is a normalized
float
,
double
and
long
double
respectively
(macro constant) |
|
FLT_MAX_EXP
DBL_MAX_EXP
LDBL_MAX_EXP
|
maximum positive integer such that
FLT_RADIX
raised by power one less than that integer is a representable finite
float
,
double
and
long
double
respectively
(macro constant) |
|
FLT_MAX_10_EXP
DBL_MAX_10_EXP
LDBL_MAX_10_EXP
|
maximum positive integer such that
10
raised to that power is a representable finite
float
,
double
and
long
double
respectively
(macro constant) |
|
default rounding mode of floating-point arithmetic
(macro constant) |
|
|
(C++11)
|
specifies in what precision all arithmetic operations are done
(macro constant) |
|
FLT_HAS_SUBNORM
DBL_HAS_SUBNORM
LDBL_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 */
See also
|
C documentation
for
Limits of floating-point types
|