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std::fetestexcept

提供: cppreference.com
< cpp‎ | numeric‎ | fenv

 
 
ニューメリックスライブラリ
一般的な数学関数
浮動小数点環境
複素数
数値配列
擬似乱数生成
コンパイル時有理数演算 (C++11)
汎用の数値演算
Original:
Generic numeric operations
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iota(C++11)
accumulate
inner_product
adjacent_difference
partial_sum
 
浮動小数点環境
機能します
Original:
Functions
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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)
マクロ定数
Original:
Macro constants
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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)
 
Defined in header <cfenv>
int fetestexcept( int excepts );
(C++11およびそれ以降)
現在設定されている浮動小数点例外の指定したサブセットのか​​を決定します。引数exceptsは、ビット単位の論理和(OR)小数点例外マクロが浮かんでいますのです.
Original:
Determines which of the specified subset of the floating point exceptions are currently set. The argument excepts is a bitwise OR of the 小数点例外マクロが浮かんでいます.
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目次

[編集] パラメータ

excepts -
テストするために例外フラグをリストするビットマスク
Original:
bitmask listing the exception flags to test
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[編集] 値を返します

ビット単位の論理和(OR)exceptsに含まれており、現在設定されている浮動小数点例外に対応してい両方の浮動小数点例外マクロの.
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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[編集]

[edit]
#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

[編集] も参照してください

指定された浮動小数点ステータスフラグをクリアします
Original:
clears the specified floating-point status flags
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(関数) [edit]