Difference between revisions of "cpp/numeric/fenv/fetestexcept"
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{{cpp/title|fetestexcept}} | {{cpp/title|fetestexcept}} | ||
| − | {{cpp/numeric/fenv/ | + | {{cpp/numeric/fenv/navbar}} |
| − | {{ | + | {{dcl begin}} |
| − | {{ | + | {{dcl header | cfenv}} |
| − | {{ | + | {{dcl | since=c++11 | |
| − | int fetestexcept(int excepts); | + | int fetestexcept( int excepts ); |
}} | }} | ||
| − | {{ | + | {{dcl end}} |
Determines which of the specified subset of the floating point exceptions are currently set. The argument {{tt|excepts}} is a bitwise OR of the [[cpp/numeric/fenv/FE_exceptions|floating point exception macros]]. | Determines which of the specified subset of the floating point exceptions are currently set. The argument {{tt|excepts}} is a bitwise OR of the [[cpp/numeric/fenv/FE_exceptions|floating point exception macros]]. | ||
===Parameters=== | ===Parameters=== | ||
| − | {{ | + | {{par begin}} |
| − | {{ | + | {{par | excepts | bitmask listing the exception flags to test}} |
| − | {{ | + | {{par end}} |
===Return value=== | ===Return value=== | ||
Bitwise OR of the floating-point exception macros that are both included in {{tt|excepts}} and correspond to floating-point exceptions currently set. | Bitwise OR of the floating-point exception macros that are both included in {{tt|excepts}} and correspond to floating-point exceptions currently set. | ||
| − | {{cpp/numeric/fenv/example1}} | + | ===Example=== |
| + | {{include| cpp/numeric/fenv/example1}} | ||
===See also=== | ===See also=== | ||
| − | {{ | + | {{dsc begin}} |
| − | {{ | + | {{dsc inc | cpp/numeric/fenv/dsc feclearexcept}} |
| − | {{ | + | {{dsc see c | c/numeric/fenv/fetestexcept}} |
| + | {{dsc end}} | ||
| + | |||
| + | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | ||
Latest revision as of 06:48, 18 September 2017
| Defined in header <cfenv>
|
||
| int fetestexcept( int excepts ); |
(since C++11) | |
Determines which of the specified subset of the floating point exceptions are currently set. The argument excepts is a bitwise OR of the floating point exception macros.
Contents |
[edit] Parameters
| excepts | - | bitmask listing the exception flags to test |
[edit] Return value
Bitwise OR of the floating-point exception macros that are both included in excepts and correspond to floating-point exceptions currently set.
[edit] Example
Run this code
#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
| (C++11) |
clears the specified floating-point status flags (function) |
| C documentation for fetestexcept
| |
