Module fenv

Floating-point environment. Handling of floating-point rounding and exceptions (overflow, division by zero, etc.).

Types

Tfenv = object

Represents the entire floating-point environment. The floating-point environment refers collectively to any floating-point status flags and control modes supported by the implementation.

Tfexcept = object

Represents the floating-point status flags collectively, including any status the implementation associates with the flags. A floating-point status flag is a system variable whose value is set (but never cleared) when a floating-point exception is raised, which occurs as a side effect of exceptional floating-point arithmetic to provide auxiliary information. A floating-point control mode is a system variable whose value may be set by the user to affect the subsequent behavior of floating-point arithmetic.

Vars

FE_DIVBYZERO: cint

division by zero

FE_INEXACT: cint

inexact result

FE_INVALID: cint

invalid operation

FE_OVERFLOW: cint

result not representable due to overflow

FE_UNDERFLOW: cint

result not representable due to underflow

FE_ALL_EXCEPT: cint

bitwise OR of all supported exceptions

FE_DOWNWARD: cint

round toward -Inf

FE_TONEAREST: cint

round to nearest

FE_TOWARDZERO: cint

round toward 0

FE_UPWARD: cint

round toward +Inf

FE_DFL_ENV: cint

macro of type pointer to fenv_t to be used as the argument to functions taking an argument of type fenv_t; in this case the default environment will be used

Procs

proc feclearexcept(excepts: cint): cint {.importc, header: "<fenv.h>".}

Clear the supported exceptions represented by excepts.

proc fegetexceptflag(flagp: ptr Tfexcept; excepts: cint): cint {.importc,
    header: "<fenv.h>".}

Store implementation-defined representation of the exception flags indicated by excepts in the object pointed to by flagp.

proc feraiseexcept(excepts: cint): cint {.importc, header: "<fenv.h>".}

Raise the supported exceptions represented by excepts.

proc fesetexceptflag(flagp: ptr Tfexcept; excepts: cint): cint {.importc,
    header: "<fenv.h>".}

Set complete status for exceptions indicated by excepts according to the representation in the object pointed to by flagp.

proc fetestexcept(excepts: cint): cint {.importc, header: "<fenv.h>".}

Determine which of subset of the exceptions specified by excepts are currently set.

proc fegetround(): cint {.importc, header: "<fenv.h>".}

Get current rounding direction.

proc fesetround(roundingDirection: cint): cint {.importc, header: "<fenv.h>".}

Establish the rounding direction represented by roundingDirection.

proc fegetenv(envp: ptr Tfenv): cint {.importc, header: "<fenv.h>".}

Store the current floating-point environment in the object pointed to by envp.

proc feholdexcept(envp: ptr Tfenv): cint {.importc, header: "<fenv.h>".}

Save the current environment in the object pointed to by envp, clear exception flags and install a non-stop mode (if available) for all exceptions.

proc fesetenv(a1: ptr Tfenv): cint {.importc, header: "<fenv.h>".}

Establish the floating-point environment represented by the object pointed to by envp.

proc feupdateenv(envp: ptr Tfenv): cint {.importc, header: "<fenv.h>".}

Save current exceptions in temporary storage, install environment represented by object pointed to by envp and raise exceptions according to saved exceptions.

Templates

template fpRadix(): int

The (integer) value of the radix used to represent any floating point type on the architecture used to build the program.

template mantissaDigits(T: typedesc[float32]): int

Number of digits (in base floatingPointRadix) in the mantissa of 32-bit floating-point numbers.

template digits(T: typedesc[float32]): int

Number of decimal digits that can be represented in a 32-bit floating-point type without losing precision.

template minExponent(T: typedesc[float32]): int

Minimum (negative) exponent for 32-bit floating-point numbers.

template maxExponent(T: typedesc[float32]): int

Maximum (positive) exponent for 32-bit floating-point numbers.

template min10Exponent(T: typedesc[float32]): int

Minimum (negative) exponent in base 10 for 32-bit floating-point numbers.

template max10Exponent(T: typedesc[float32]): int

Maximum (positive) exponent in base 10 for 32-bit floating-point numbers.

template minimumPositiveValue(T: typedesc[float32]): float32

The smallest positive (nonzero) number that can be represented in a 32-bit floating-point type.

template maximumPositiveValue(T: typedesc[float32]): float32

The largest positive number that can be represented in a 32-bit floating-point type.

template epsilon(T: typedesc[float32]): float32

The difference between 1.0 and the smallest number greater than 1.0 that can be represented in a 32-bit floating-point type.

template mantissaDigits(T: typedesc[float64]): int

Number of digits (in base floatingPointRadix) in the mantissa of 64-bit floating-point numbers.

template digits(T: typedesc[float64]): int

Number of decimal digits that can be represented in a 64-bit floating-point type without losing precision.

template minExponent(T: typedesc[float64]): int

Minimum (negative) exponent for 64-bit floating-point numbers.

template maxExponent(T: typedesc[float64]): int

Maximum (positive) exponent for 64-bit floating-point numbers.

template min10Exponent(T: typedesc[float64]): int

Minimum (negative) exponent in base 10 for 64-bit floating-point numbers.

template max10Exponent(T: typedesc[float64]): int

Maximum (positive) exponent in base 10 for 64-bit floating-point numbers.

template minimumPositiveValue(T: typedesc[float64]): float64

The smallest positive (nonzero) number that can be represented in a 64-bit floating-point type.

template maximumPositiveValue(T: typedesc[float64]): float64

The largest positive number that can be represented in a 64-bit floating-point type.

template epsilon(T: typedesc[float64]): float64

The difference between 1.0 and the smallest number greater than 1.0 that can be represented in a 64-bit floating-point type.