std::fetestexcept(3)

💖 NAME 💖

okay bestie, we're in std::fetestexcept(3) from the C++ Standard Libary, and the name is literally:

std::fetestexcept — std::fetestexcept

yes that's the whole name section. iconic, no notes. 💅

✨ Synopsis ✨

Defined in header <cfenv>:

int fetestexcept( int excepts );  (since C++11)

std::fetestexcept 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. slay.

🌸 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. periodt.

🔥 Example 🔥

// Run this code

        #include <cfenv>
        #include <cmath>
        #include <iostream>

        // #pragma STDC FENV_ACCESS ON

        volatile double zero = 0.0; // volatile not needed where FENV_ACCESS is
       supported
        volatile double one = 1.0;  // volatile not needed where FENV_ACCESS is
       supported

        int main()
        {
            std::feclearexcept(FE_ALL_EXCEPT);
            std::cout <<  "1.0/0.0 = " << 1.0 / zero << '\n';
            if (std::fetestexcept(FE_DIVBYZERO))
                std::cout << "division by zero reported\n";
            else
                std::cout << "division by zero not reported\n";

            std::feclearexcept(FE_ALL_EXCEPT);
            std::cout << "1.0/10 = " << one / 10 << '\n';
            if (std::fetestexcept(FE_INEXACT))
                std::cout << "inexact result reported\n";
            else
                std::cout << "inexact result not reported\n";

            std::feclearexcept(FE_ALL_EXCEPT);
            std::cout << "sqrt(-1) = " << std::sqrt(-1) << '\n';
            if (std::fetestexcept(FE_INVALID))
                std::cout << "invalid result reported\n";
            else
                std::cout << "invalid result not reported\n";
        }

Possible output:

        1.0/0.0 = inf
        division by zero reported
        1.0/10 = 0.1
        inexact result reported
        sqrt(-1) = -nan
        invalid result reported

🌈 See also 🌈

• feclearexcept — clears the specified floating-point status flags (C++11) (function)
• C documentation for fetestexcept

catch you later bestie 🫶 — this page is std::fetestexcept(3), sourced from http://cppreference.com, version/date 2024.06.10 💅✨