| Functions | ||||
(C99) | ||||
fetestexcept (C99) | ||||
(C99) | ||||
(C99)(C99) | ||||
(C99)(C99) | ||||
(C99) | ||||
(C99) | ||||
(C99) | ||||
| Macro constants | ||||
(C99) |
Defined in header <fenv.h> | ||
int fetestexcept(int excepts); | (since C99) | |
Determines which of the specified subset of the floating-point exceptions are currently set. The argumentexcepts is a bitwise OR of thefloating-point exception macros.
Contents |
| excepts | - | bitmask listing the exception flags to test |
Bitwise OR of the floating-point exception macros that are both included inexcepts and correspond to floating-point exceptions currently set.
#include <stdio.h>#include <math.h>#include <fenv.h>#include <float.h> #pragma STDC FENV_ACCESS ON void show_fe_exceptions(void){printf("current exceptions raised: ");if(fetestexcept(FE_DIVBYZERO))printf(" FE_DIVBYZERO");if(fetestexcept(FE_INEXACT))printf(" FE_INEXACT");if(fetestexcept(FE_INVALID))printf(" FE_INVALID");if(fetestexcept(FE_OVERFLOW))printf(" FE_OVERFLOW");if(fetestexcept(FE_UNDERFLOW))printf(" FE_UNDERFLOW");if(fetestexcept(FE_ALL_EXCEPT)==0)printf(" none");printf("\n");} int main(void){/* Show default set of exception flags. */ show_fe_exceptions(); /* Perform some computations which raise exceptions. */printf("1.0/0.0 = %f\n",1.0/0.0);/* FE_DIVBYZERO */printf("1.0/10.0 = %f\n",1.0/10.0);/* FE_INEXACT */printf("sqrt(-1) = %f\n",sqrt(-1));/* FE_INVALID */printf("DBL_MAX*2.0 = %f\n",DBL_MAX*2.0);/* FE_INEXACT FE_OVERFLOW */printf("nextafter(DBL_MIN/pow(2.0,52),0.0) = %.1f\n",nextafter(DBL_MIN/pow(2.0,52),0.0));/* FE_INEXACT FE_UNDERFLOW */ show_fe_exceptions(); return0;}
Output:
current exceptions raised: none1.0/0.0 = inf1.0/10.0 = 0.100000sqrt(-1) = -nanDBL_MAX*2.0 = infnextafter(DBL_MIN/pow(2.0,52),0.0) = 0.0current exceptions raised: FE_DIVBYZERO FE_INEXACT FE_INVALID FE_OVERFLOW FE_UNDERFLOW
(C99) | clears the specified floating-point status flags (function)[edit] |
C++ documentation forfetestexcept | |
