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FE_DIVBYZERO, FE_INEXACT, FE_INVALID, FE_OVERFLOW, FE_UNDERFLOW, FE_ALL_EXCEPT

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< 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>
#define FE_DIVBYZERO    /*implementation defined power of 2*/
(C + + 11以来)
#define FE_INEXACT      /*implementation defined power of 2*/
(C + + 11以来)
#define FE_INVALID      /*implementation defined power of 2*/
(C + + 11以来)
#define FE_OVERFLOW     /*implementation defined power of 2*/
(C + + 11以来)
#define FE_UNDERFLOW    /*implementation defined power of 2*/
(C + + 11以来)
#define FE_ALL_EXCEPT  FE_DIVBYZERO | FE_INEXACT | \

                       FE_INVALID | FE_OVERFLOW |  \

                       FE_UNDERFLOW
(C + + 11以来)
これらのすべてのマクロ定数(FE_ALL_EXCEPT除く)2の異なる累乗の整数定数式に展開し、独自にサポートされているすべての浮動小数点例外を識別する。それがサポートされている場合、それぞれのマクロは、定義されています.
Original:
All these macro constants (except FE_ALL_EXCEPT) expand to integer constant expressions that are distinct powers of 2, which uniquely identify all supported floating-point exceptions. Each macro is only defined if it is supported.
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ビット単位の論理和(OR)他のすべてのFE_ALL_EXCEPTに展開されるマクロ定数FE_*は、常に定義されており、浮動小数点例外が実装によってサポートされていない場合はゼロになります。.
Original:
The macro constant FE_ALL_EXCEPT, which expands to the bitwise OR of all other FE_*, is always defined and is zero if floating-point exceptions are not supported by the implementation.
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定数
Original:
Constant
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Explanation
FE_DIVBYZERO
ゼロによる除算は、以前の浮動小数点演算中に発生しました
Original:
division by zero occurred during the earlier floating-point operation
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FE_INEXACT
結果が不正確:丸めは、以前の浮動小数点演算の結果を格納する必要がありました
Original:
inexact result: rounding was necessary to store the result of the earlier floating-point operation
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FE_INVALID
無効な操作:以前の浮動小数点演算が実行できませんでした
Original:
invalid operation: the earlier floating-point operation could not performed
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FE_OVERFLOW
以前の浮動小数点演算の結果が表現可能であるには余りにも大きかった
Original:
the result of the earlier floating-point operation was too large to be representable
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FE_UNDERFLOW
以前の浮動小数点演算の結果が非正規だった
Original:
the result of the earlier floating-point operation was subnormal
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FE_ALL_EXCEPT
ビット単位の論理和(OR)すべてのサポートされている浮動小数点例外の
Original:
bitwise OR of all supported floating-point exceptions
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実装では、追加の浮動小数点例外を識別するために<cfenv>で追加のマクロ定数を定義することができます。すべてのそのような定数は少なくともひとつの大文字が続くFE_で始まる.
Original:
The implementation may define additional macro constants in <cfenv> to identify additional floating-point exceptions. All such constants begin with FE_ followed by at least one uppercase letter.
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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

一般的な数学関数で使用されるエラー処理機構を定義しています
Original:
defines the error handling mechanism used by the common mathematical functions
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(マクロ定数) [edit]