fetestexcept
From cppreference.com
| 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 argument excepts is a bitwise OR of the floating point exception macros.
Parameters
| excepts | - | bitmask listing the exception flags to test |
Return value
Bitwise OR of the floating-point exception macros that are both included in excepts and correspond to floating-point exceptions currently set.
Example
Run this code
#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(); return 0; }
Output:
current exceptions raised: none 1.0/0.0 = inf 1.0/10.0 = 0.100000 sqrt(-1) = -nan DBL_MAX*2.0 = inf nextafter(DBL_MIN/pow(2.0,52),0.0) = 0.0 current exceptions raised: FE_DIVBYZERO FE_INEXACT FE_INVALID FE_OVERFLOW FE_UNDERFLOW
References
- C11 standard (ISO/IEC 9899:2011):
- 7.6.2.5 The fetestexcept function (p: 211-212)
- C99 standard (ISO/IEC 9899:1999):
- 7.6.2.5 The fetestexcept function (p: 192-193)
See also
| (C99) |
clears the specified floating-point status flags (function) |