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Difference between revisions of "cpp/numeric/fenv/feclearexcept"

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< cpp‎ | numeric‎ | fenv
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{{cpp/title|feclearexcept}}
 
{{cpp/title|feclearexcept}}
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{{dcl begin}}
{{ddcl list header | cfenv}}
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{{dcl header | cfenv}}
{{ddcl list item | notes={{mark since c++11}} |
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{{dcl | since=c++11 |
int feclearexcept(int excepts);
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int feclearexcept( int excepts );
 
}}
 
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{{dcl end}}
  
 
Attempts to clear the floating-point exceptions that are listed in the bitmask argument {{tt|excepts}}, which is a bitwise OR of the [[cpp/numeric/fenv/FE_exceptions|floating point exception macros]].
 
Attempts to clear the floating-point exceptions that are listed in the bitmask argument {{tt|excepts}}, which is a bitwise OR of the [[cpp/numeric/fenv/FE_exceptions|floating point exception macros]].
  
 
===Parameters===
 
===Parameters===
{{param list begin}}
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{{par begin}}
{{param list item | excepts | bitmask listing the exception flags to clear}}
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{{par | excepts | bitmask listing the exception flags to clear}}
{{param list end}}
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{{par end}}
  
 
===Return value===
 
===Return value===
 
{{c|0}} if all indicated exceptions were successfully cleared or if {{tt|excepts}} is zero. Returns a non-zero value on error.
 
{{c|0}} if all indicated exceptions were successfully cleared or if {{tt|excepts}} is zero. Returns a non-zero value on error.
  
{{cpp/numeric/fenv/example1}}
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===Example===
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{{include| cpp/numeric/fenv/example1}}
  
 
===See also===
 
===See also===
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{{dsc begin}}
{{dcl list template | cpp/numeric/fenv/dcl list fetestexcept}}
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{{dsc inc | cpp/numeric/fenv/dsc fetestexcept}}
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{{dsc see c | c/numeric/fenv/feclearexcept}}
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{{dsc end}}
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Latest revision as of 06:50, 18 September 2017

 
 
 
Floating-point environment
Functions
feclearexcept
(C++11)
(C++11)(C++11)
(C++11)(C++11)
Macro constants
(C++11)
 
Defined in header <cfenv>
int feclearexcept( int excepts );
(since C++11)

Attempts to clear the floating-point exceptions that are listed in the bitmask argument excepts, which is a bitwise OR of the floating point exception macros.

Contents

[edit] Parameters

excepts - bitmask listing the exception flags to clear

[edit] Return value

0 if all indicated exceptions were successfully cleared or if excepts is zero. Returns a non-zero value on error.

[edit] Example

#include <cfenv>
#include <cmath>
#include <iostream>
 
// #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 << "division 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";
}

Possible output:

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

[edit] See also

determines which of the specified floating-point status flags are set
(function) [edit]
C documentation for feclearexcept