std::feraiseexcept (3) - Linux Manuals

std::feraiseexcept: std::feraiseexcept

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