std::feclearexcept

< cpp‎ | numeric‎ | fenv

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Numerik-Bibliothek
Gemeinsame mathematischen Funktionen
Floating-Point-Umgebung
Komplexe Zahlen
Numerische Arrays
Pseudo-Zufallszahlen
Compile-time rationale Arithmetik (C++11)
Generische numerische Operationen
Original:
Generic numeric operations
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 iota (C++11)
 accumulate
 inner_product
 partial_sum

Floating-Point-Umgebung
Funktionen
Original:
Functions
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 feclearexcept (C++11)
 fetestexcept (C++11)
 feraiseexcept (C++11)
 fegetexceptflagfesetexceptflag (C++11)(C++11)
 fegetroundfesetround (C++11)(C++11)
 fegetenvfesetenv (C++11)
 feholdexcept (C++11)
 feupdateenv (C++11)
Makro Konstanten
Original:
Macro constants
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 FE_ALL_EXCEPTFE_DIVBYZEROFE_INEXACTFE_INVALIDFE_OVERFLOWFE_UNDERFLOW (C++11)
 FE_DOWNWARDFE_TONEARESTFE_TOWARDZEROFE_UPWARD (C++11)
 FE_DFL_ENV (C++11)

 Defined in header int feclearexcept( int excepts ); (seit C++11)
Versuche, die Floating-Point-Ausnahmen, die in der Bitmaske Argument `excepts`, die eine bitweise OR der Gleitkomma-Ausnahme Makros aufgelistet sind .
Original:
Attempts to clear the floating-point exceptions that are listed in the bitmask argument `excepts`, which is a bitwise OR of the Gleitkomma-Ausnahme Makros.
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Inhaltsverzeichnis

[Bearbeiten]Parameter

 excepts - Bitmaske auflistet Ausnahme Flags zu löschenOriginal: bitmask listing the exception flags to clearThe text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

[Bearbeiten]Rückgabewert

0 wenn alle angegebenen Ausnahmen wurden erfolgreich gelöscht oder wenn `excepts` Null ist. Gibt einen Wert ungleich Null auf Fehler .
Original:
0 if all indicated exceptions were successfully cleared or if `excepts` is zero. Returns a non-zero value on error.
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[Bearbeiten]Beispiel

```#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```

[Bearbeiten]Siehe auch

 fetestexcept(C++11) bestimmt, welche der angegebenen Gleitkommazahl Status-Flags gesetzt sindOriginal: determines which of the specified floating-point status flags are setThe text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (Funktion)