| Functions | ||||
(C99) | ||||
(C99) | ||||
(C99) | ||||
fegetexceptflagfesetexceptflag (C99)(C99) | ||||
(C99)(C99) | ||||
(C99) | ||||
(C99) | ||||
(C99) | ||||
| Macro constants | ||||
(C99) |
Defined in header <fenv.h> | ||
int fegetexceptflag( fexcept_t* flagp,int excepts); | (1) | (since C99) |
int fesetexceptflag(const fexcept_t* flagp,int excepts); | (2) | (since C99) |
1) Attempts to obtain the full contents of the floating-point exception flags that are listed in the bitmask argumentexcepts, which is a bitwise OR of thefloating-point exception macros.
2) Attempts to copy the full contents of the floating-point exception flags that are listed inexcepts fromflagp into the floating-point environment. Does not raise any exceptions, only modifies the flags.
The full contents of a floating-point exception flag is not necessarily a boolean value indicating whether the exception is raised or cleared. For example, it may be a struct which includes the boolean status and the address of the code that triggered the exception. These functions obtain all such content and obtain/store it inflagp in implementation-defined format.
Contents |
| flagp | - | pointer to anfexcept_t object where the flags will be stored or read from |
| excepts | - | bitmask listing the exception flags to get/set |
0 on success, non-zero otherwise.
#include <stdio.h>#include <fenv.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){ fexcept_t excepts; /* Setup a "current" set of exception flags. */feraiseexcept(FE_INVALID); show_fe_exceptions(); /* Save current exception flags. */ fegetexceptflag(&excepts,FE_ALL_EXCEPT); /* Temporarily raise two other exceptions. */feclearexcept(FE_ALL_EXCEPT);feraiseexcept(FE_OVERFLOW|FE_INEXACT); show_fe_exceptions(); /* Restore previous exception flags. */ fesetexceptflag(&excepts,FE_ALL_EXCEPT); show_fe_exceptions(); return0;}
Output:
current exceptions raised: FE_INVALIDcurrent exceptions raised: FE_INEXACT FE_OVERFLOWcurrent exceptions raised: FE_INVALID
C++ documentation forfegetexceptflag,fesetexceptflag |
