std::fetestexcept
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fetestexcept
(C++11)
(C++11)
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(C++11)
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 documentation for fetestexcept