std/fenv

Floating-point environment. Handling of floating-point rounding and exceptions (overflow, division by zero, etc.). The types, vars and procs are bindings for the C standard library <fenv.h> header.

Types

Tfenv {.importc: "fenv_t", header: "<fenv.h>", final, pure.} = 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. Source Edit

Tfexcept {.importc: "fexcept_t", header: "<fenv.h>", final, pure.} = 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. Source Edit

Vars

FE_ALL_EXCEPT {.importc, header: "<fenv.h>".}: cint

bitwise OR of all supported exceptions Source Edit

FE_DFL_ENV {.importc, header: "<fenv.h>".}: 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 Source Edit

FE_DIVBYZERO {.importc, header: "<fenv.h>".}: cint

division by zero Source Edit

FE_DOWNWARD {.importc, header: "<fenv.h>".}: cint

round toward -Inf Source Edit

FE_INEXACT {.importc, header: "<fenv.h>".}: cint

inexact result Source Edit

FE_INVALID {.importc, header: "<fenv.h>".}: cint

invalid operation Source Edit

FE_OVERFLOW {.importc, header: "<fenv.h>".}: cint

result not representable due to overflow Source Edit

FE_TONEAREST {.importc, header: "<fenv.h>".}: cint

round to nearest Source Edit

FE_TOWARDZERO {.importc, header: "<fenv.h>".}: cint

round toward 0 Source Edit

FE_UNDERFLOW {.importc, header: "<fenv.h>".}: cint

result not representable due to underflow Source Edit

FE_UPWARD {.importc, header: "<fenv.h>".}: cint

round toward +Inf Source Edit

Procs

proc feclearexcept(excepts: cint): cint {.importc, header: "<fenv.h>",
    ...raises: [], tags: [], forbids: [].}

Clear the supported exceptions represented by excepts. Source Edit

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

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

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

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

proc fegetround(): cint {.importc, header: "<fenv.h>", ...raises: [], tags: [],
                          forbids: [].}

Get current rounding direction. Source Edit

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

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. Source Edit

proc feraiseexcept(excepts: cint): cint {.importc, header: "<fenv.h>",
    ...raises: [], tags: [], forbids: [].}

Raise the supported exceptions represented by excepts. Source Edit

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

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

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

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

proc fesetround(roundingDirection: cint): cint {.importc, header: "<fenv.h>",
    ...raises: [], tags: [], forbids: [].}

Establish the rounding direction represented by roundingDirection. Source Edit

proc fetestexcept(excepts: cint): cint {.importc, header: "<fenv.h>",
    ...raises: [], tags: [], forbids: [].}

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

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

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

Templates

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

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

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

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

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. Source Edit

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. Source Edit

template fpRadix(): int

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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