The feupdateenv() function is defined in <cfenv> header file.
feupdateenv() prototype
int feupdateenv( fenv_t* envp );
The feupdateenv() function takes a pointer of type fenv_t as its argument which holds a floating point environment previously set by using feholdexcept or fegetenv and restores that floating point environment along with the current environment.
feupdateenv() Parameters
- envp: Pointer to the fenv_t object that is set by an earlier call to feholdexcept or fegetenv or is equal to FE_DFL_ENV.
feupdateenv() Return value
- On success, the feupdateenv() function returns 0.
- On failure, it returns nonzero.
Example: How feupdateenv() function works?
#include <iostream>
#include <cmath>
#include <cfenv>
#pragma STDC FENV_ACCESS ON
using namespace std;
void print_exceptions()
{
cout << "Raised exceptions: ";
if(fetestexcept(FE_ALL_EXCEPT))
{
if(fetestexcept(FE_DIVBYZERO))
cout << "FE_DIVBYZERO ";
if(fetestexcept(FE_INEXACT))
cout << "FE_INEXACT ";
if(fetestexcept(FE_INVALID))
cout << "FE_INVALID ";
if(fetestexcept(FE_OVERFLOW))
cout << "FE_OVERFLOW ";
if(fetestexcept(FE_UNDERFLOW))
cout << "FE_UNDERFLOW ";
}
else
cout << "None";
cout << endl;
}
int main()
{
fenv_t envp;
/* raise certain exceptions */
feraiseexcept(FE_INVALID|FE_DIVBYZERO);
print_exceptions();
/* saves and clears current exceptions */
feupdateenv(&envp);
print_exceptions();
/* restores saved exceptions */
feupdateenv(&envp);
print_exceptions();
return 0;
}
When you run the program, the output will be:
Raised exceptions: FE_DIVBYZERO FE_INVALID Raised exceptions: None Raised exceptions: FE_DIVBYZERO FE_INVALID