std::fetestexcept

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C++

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Generici operazioni numeriche Original: Generic numeric operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

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Virgola mobile ambiente

Funzioni Original: Functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

feclearexcept (C++11)

fetestexcept (C++11)

feraiseexcept (C++11)

fegetexceptflag fesetexceptflag (C++11) (C++11)

fegetround fesetround (C++11) (C++11)

fegetenv fesetenv (C++11)

feholdexcept (C++11)

feupdateenv (C++11)

Macro costanti Original: Macro constants The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

FE_ALL_EXCEPT FE_DIVBYZERO FE_INEXACT FE_INVALID FE_OVERFLOW FE_UNDERFLOW (C++11)

FE_DOWNWARD FE_TONEAREST FE_TOWARDZERO FE_UPWARD (C++11)

FE_DFL_ENV (C++11)

 

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Elemento definito nell'header <cfenv>
int fetestexcept( int excepts );		(dal C++11)

Determina quale delle sottoinsieme specificato delle eccezioni in virgola mobile sono attualmente impostato. Il excepts argomento è un OR bit per bit del galleggiante macro di eccezione.

Original:

Determines which of the specified subset of the floating point exceptions are currently set. The argument excepts is a bitwise OR of the galleggiante macro di eccezione.

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Parametri

excepts

-

maschera di bit che elenca le bandiere eccezione per testare Original: bitmask listing the exception flags to test The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

Valore di ritorno

OR bit per bit dei virgola mobile macro eccezioni che sono entrambi inclusi in excepts e corrispondono alle eccezioni a virgola mobile attualmente impostato.

Original:

Bitwise OR of the floating-point exception macros that are both included in excepts and correspond to floating-point exceptions currently set.

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Esempio

#include <iostream>
#include <cfenv>
#include <cmath>

#pragma STDC FENV_ACCESS ON

volatile double zero = 0.0; // volatile not needed where FENV_ACCESS is supported
volatile double one = 1.0;  // volatile not needed where FENV_ACCESS is supported

int main()
{
    std::feclearexcept(FE_ALL_EXCEPT);
    std::cout <<  "1.0/0.0 = " << 1.0 / zero << '\n';
    if(std::fetestexcept(FE_DIVBYZERO)) {
        std::cout << "division by zero reported\n";
    } else {
        std::cout << "divsion by zero not reported\n";
    }

    std::feclearexcept(FE_ALL_EXCEPT);
    std::cout << "1.0/10 = " << one/10 << '\n';
    if(std::fetestexcept(FE_INEXACT)) {
        std::cout << "inexact result reported\n";
    } else {
        std::cout << "inexact result not reported\n";
    }

    std::feclearexcept(FE_ALL_EXCEPT);
    std::cout << "sqrt(-1) = " << std::sqrt(-1) << '\n';
    if(std::fetestexcept(FE_INVALID)) {
        std::cout << "invalid result reported\n";
    } else {
        std::cout << "invalid result not reported\n";
    }
}

Output:

1.0/0.0 = inf
division by zero reported
1.0/10 = 0.1
inexact result reported
sqrt(-1) = -nan
invalid result reported

Vedi anche

feclearexcept (C++11)	cancella le specificati virgola mobile flag di stato Original: clears the specified floating-point status flags The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (funzione)