math/test/git_issue_826.cpp

// Copyright Nicholas McKibben, 2022
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0. (See accompanying file
// LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_MATH_BUILD_MODULE
#include <boost/math/distributions/beta.hpp>
#else
import boost.math;
#endif

#ifndef BOOST_MATH_BUILD_MODULE
#include <iostream>
#include <iomanip>
#endif

// FE_ALL_EXCEPT / FE_OVERFLOW come from the pure-C header, which is safe to
// include textually alongside import std. feclearexcept / fetestexcept are the
// global functions it declares (the std:: overloads would need <cfenv>, which
// must not be included in module mode).
#include <fenv.h>

#include "math_unit_test.hpp"

#pragma STDC FENV_ACCESS ON

int main()
{
    constexpr double q {0.999995};
    constexpr double a {2};
    constexpr double b {99999};
    feclearexcept(FE_ALL_EXCEPT);
    boost::math::beta_distribution<double> d {a, b};
    const auto ans = boost::math::quantile(d, q);
    if (fetestexcept(FE_OVERFLOW))
    {
        std::cout << "overflow reported" << std::endl;
    }
    else
    {
        std::cout << "overflow not reported" << std::endl;
    }
    std::cout << std::setprecision(16) << "Ans is: " << ans << std::endl;

    CHECK_ULP_CLOSE(ans, 0.000149761910560502, 1);

    return boost::math::test::report_errors();
}
// overflow reported
// Ans is: 0.000149761910560502