| Name | Description | Notes | Source | Availability | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
CMPLXL() |
Create constant of type
long double complex |
? | M | (·) | <complex.h> |
C11 | |||||
LDBL_ |
Representable decimal digits in any real floating-point type | L | M | <float.h> |
C89 | C90 | C95 | C99 | C11 | ||
LDBL_ |
Decimal digits of precision of
long double |
L | M | <float.h> |
C89 | C90 | C95 | C99 | C11 | ||
LDBL_ |
Smallest x of type
long double such that
1.0 + x != 1.0 |
L | M | <float.h> |
C89 | C90 | C95 | C99 | C11 | ||
LDBL_ |
Determinant whether
long double has subnormal
values |
L | M | <float.h> |
C11 | ||||||
LDBL_ |
Number of base-FLT_ digits in mantissa
of
long double |
L | M | <float.h> |
C89 | C90 | C95 | C99 | C11 | ||
LDBL_ |
Maximum value of
long double |
L | M | <float.h> |
C89 | C90 | C95 | C99 | C11 | ||
LDBL_ |
Maximum integral base-10 exponent yielding
long double |
L | M | <float.h> |
C89 | C90 | C95 | C99 | C11 | ||
LDBL_ |
One plus maximum integral exponent of base
FLT_ yielding
long double |
L | M | <float.h> |
C89 | C90 | C95 | C99 | C11 | ||
LDBL_ |
Minimum normalized value of
long double |
L | M | <float.h> |
C89 | C90 | C95 | C99 | C11 | ||
LDBL_ |
Minimum integral base-10 exponent yielding
normalized
long double |
L | M | <float.h> |
C89 | C90 | C95 | C99 | C11 | ||
LDBL_ |
One plus minimum integral exponent of base
FLT_ yielding normalized
long double |
L | M | <float.h> |
C89 | C90 | C95 | C99 | C11 | ||
LDBL_ |
Minimum positive value of
long double |
L | M | <float.h> |
C11 | ||||||
long double |
‘Long’ floating-point type | L | T | Native | C89 | C90 | C95 | C99 | C11 | ||
long double _Complex |
‘Long’ floating-point complex type | L | ? | T | Native | C99 | C11 | ||||
long double _Imaginary |
‘Long’ floating-point imaginary type | L | ? | T | Native | C99 | C11 | ||||
long double complex |
‘Long’ floating-point complex type | ? | T | <complex.h> |
C99 | C11 | |||||
long double imaginary |
‘Long’ floating-point imaginary type | ? | T | <complex.h> |
C99 | C11 | |||||
long double is intended to be a native
real
floating-point type of a natural size, capable of
representing a practical range of real numbers. (double is
usually less capable but more compact.) A floating-point
constant of type long double is suffixed with an
l or L.
Various macros in <float.h> describe the capabilities of
long double. It supports
LDBL_ decimal digits of precision, or
LDBL_ digits in the native
base FLT_.
long double has a range of ±LDBL_.
The smallest positive non-zero value it can take is
LDBL_, which could be
subnormal. The smallest positive normalized value it can take is
LDBL_.
From C11, if subnormal values are
possible,
LDBL_ expands to
1. If not, it expends to 0. If it is undeterminable, it expands to
-1.
LDBL_ is the lowest
integer x that you can give to
powl(10.0L, x) and still get a
normalized value.
LDBL_ is the highest
integer x that you can give to
powl(10.0L, x) and still get a
normalized value.
LDBL_ is the lowest integer
x that you can give to powl(FLT_ and still get a
normalized value.
LDBL_ is the highest integer
x that you can give to powl(FLT_ and still get a
normalized value.
LDBL_ is the smallest value you can
add to 1.0L to yield something other
than 1.0L.
LDBL_ is the number of
decimal digits that long double can retain without rounding
error.
From C99, if __STDC_ is
defined,
long double _Complex is a complex floating-point
type that has the same representation as an array of two long doubles, the first being the real
part, and the second the imaginary part, of the complex
number it represents. If imaginary is defined in <complex.h>,
long double _Imaginary is an imaginary floating-point
type that has the same representation as a long double.
long double imaginary and
long double complex are alternative names for
these types, available in <complex.h>.
#include <complex.h>
long double complex CMPLXL(long double re, long double im);
The macro
CMPLXL expands to a constant
expression suitable to initialize a
long double complex with static
or thread-local storage, with a value
re + I *
im, a complex number with a real component
re and an imaginary component
im, provided re
and im are similarly suitable.
If
CMPLXL is unavailable, a portable
implementation could be:
#define CMPLXL(RE, IM) \ (*(long double _Complex *) (long double[2]) { (RE), (IM) })
This information derives from a comp.std.c thread in May 2009.
TODO: This needs checking.
A value of type
long double complex can be split into
cartesian co-ordinates with creall and cimagl, or into polar co-ordinates
with cargl and cabsl.
