NAME¶

std::feraiseexcept - std::feraiseexcept

Synopsis¶

Defined in header <cfenv>
int feraiseexcept( int excepts ); (since C++11)

Attempts to raise all floating point exceptions listed in excepts (a bitwise OR of
the floating point exception macros). If one of the exceptions is FE_OVERFLOW or
FE_UNDERFLOW, this function may additionally raise FE_INEXACT. The order in which
the exceptions are raised is unspecified, except that FE_OVERFLOW and FE_UNDERFLOW
are always raised before FE_INEXACT.

Parameters¶

excepts - bitmask listing the exception flags to raise

Return value¶

0 if all listed exceptions were raised, non-zero value otherwise.

Example¶

// Run this code

#include <iostream>
#include <cfenv>

#pragma STDC FENV_ACCESS ON

int main()
{
std::feclearexcept(FE_ALL_EXCEPT);
int r = std::feraiseexcept(FE_UNDERFLOW | FE_DIVBYZERO);
std::cout << "Raising divbyzero and underflow simultaneously "
<< (r?"fails":"succeeds") << " and results in\n";
int e = std::fetestexcept(FE_ALL_EXCEPT);
if (e & FE_DIVBYZERO) {
std::cout << "division by zero\n";
}
if (e & FE_INEXACT) {
std::cout << "inexact\n";
}
if (e & FE_INVALID) {
std::cout << "invalid\n";
}
if (e & FE_UNDERFLOW) {
std::cout << "underflow\n";
}
if (e & FE_OVERFLOW) {
std::cout << "overflow\n";
}
}

Output:¶

Raising divbyzero and underflow simultaneously succeeds and results in
division by zero
underflow

See also¶

feclearexcept clears the specified floating-point status flags
(C++11) (function)
fetestexcept determines which of the specified floating-point status flags are set
(C++11) (function)