10.1: Introduction |
10.2: Function descriptions |
T denorm_min(T) throw;
Minimum positive denormalized value. Available for floating-point
types only.
int digits(T);
The number of radix digits (read: bits) in the mantissa. Also
works for integer types. The official definition is "number of
radix digits that can be represented without change".
int digits10(T);
The number of base-10 digits that can be represented without
change.
T epsilon(T);
The smallest amount which can be added to 1 to produce
a result which is not 1. Floating-point types only.
bool has_denorm(T);
True if the representation allows denormalized values (floating-point
only).
bool has_denorm_loss(T);
True if a loss of precision is detected as a denormalization loss, rather
than as an inexact result (floating-point only).
bool has_infinity(T);
True if there is a special representation for the value "infinity".
If true, the representation can be obtained by calling infinity(T)
.
bool has_quiet_NaN(T);
True if there is a special representation for a quiet (non-signalling)
Not A Number (NaN). If so, use the function quiet_NaN(T)
to obtain
it.
bool has_signaling_NaN(T);
bool has_signalling_NaN(T);
True if there is a special representation for a signalling
Not A Number (NaN). If so, use the function signalling_NaN(T)
to obtain it.
T huge(T) throw;
Returns the maximum finite representable value. Equivalent to
CHAR_MAX
, SHRT_MAX
, FLT_MAX
, etc. For floating types
with denormalization, the maximum positive normalized value is
returned.
T infinity(T) throw;
Returns the representation of positive infinity, if available.
Note that you should check availability with has_infinity(T)
before calling this function.
bool is_bounded(T);
True if the set of values represented by the type is finite.
All built-in types are bounded. (This function was provided
so that e.g. arbitrary precision types could be distinguished).
bool is_exact(T);
True if the representation is exact. All integer types are
exact; floating-point types generally aren't. A rational
arithmetic type could be exact.
bool is_iec559(T);
True if the type conforms to the IEC 559 standard. IEC is
the International Electrotechnical Commission. Note that
IEC 559 is the same as IEEE 754. Only relevant for floating types.
bool is_integer(T);
True if the type is integer.
bool is_modulo(T);
True if the type is modulo. Integer types are usually
modulo: if you add two integers, they might wrap around
and give you a small result. (Some special kinds of
integers don't wrap around, but stop at an upper or
lower bound; this is called saturating arithmetic).
This is false for floating types.
bool is_signed(T);
True if the type is signed (i.e. can handle both positive
and negative values).
int max_exponent(T);
The maximum exponent (Max_exp) is the maximum positive integer such that
the radix (read: 2) raised to the power Max_exp-1 is a representable,
finite floating point number. Floating types only.
int max_exponent10(T);
The maximum base-10 exponent (Max_exp10) is the maximum positive integer
such that 10 raised to the power Max_exp10 is a representable,
finite floating point number. Floating types only.
int min_exponent(T);
The minimum exponent (Min_exp) is the minimum negative integer
such that the radix (read: 2) raised to the power Min_exp-1 is
a normalized floating point number. Floating types only.
int min_exponent10(T);
The minimum base-10 exponent (Min_exp10) is the minimum negative
integer such that 10 raised to the power Min_exp10 is in the
range of normalized floating point numbers.
T neghuge(T);
This returns the maximally negative value for a type.
For integers, this is the same as min(). For floating-point
types, it is - huge(T())
.
T one(T);
Returns a representation for "1".
int precision(T);
Same as digits10()
.
T quiet_NaN(T) throw;
Returns the representation for a quiet (non-signalling) Not A Number
(NaN), if available. You should check availability using the
has_quiet_NaN(T)
function first.
int radix(T);
For floating-point types, this returns the radix (base) of the
exponent. For integers, it specifies the base of the representation.
Range range(T);
Returns Range(min_exponent10(T()), max_exponent10(T()))
, i.e.
the range of representable base-10 exponents.
T round_error(T) throw;
Returns a measure of the maximum rounding error for floating-point types.
This will typically be 0.5
.
std::float_round_style round_style(T);
Returns the current rounding style for floating-point arithmetic.
The possibilities are: round_indeterminate
(i.e. don't have a clue),
round_toward_zero
, round_to_nearest
(round to nearest
representable value), round_toward_infinity
(round toward
positive infinity), and round_neg_infinity
(round toward
negative infinity).
T signaling_NaN(T) throw;
T signalling_NaN(T) throw;
Returns the representation for a signalling Not A Number (NaN),
if available. You should check availability by calling
has_signalling_NaN(T)
first.
T tiny(T);
For integer types, this returns the minimum finite value, which may be
negative. For floating types, it returns the minimum positive value.
For floating types with denormalization, the function
returns the minimum positive normalized value.
T tinyness_before(T);
True if tinyness is detected before rounding. Other than this
description, I don't have a clue what this means; anyone have
a copy of IEC 559/IEEE 754 floating around?