//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include <cassert>
#include <cstddef>
#include <ios>
#include <locale>
#include <streambuf>
#include <string>

class my_facet : public std::num_get<char, const char*> {
public:
    explicit my_facet(std::size_t refs = 0) : std::num_get<char, const char*>(refs) {}
};

class my_numpunct : public std::numpunct<char> {
protected:
    virtual char_type do_thousands_sep() const {
        return '_';
    }
    virtual std::string do_grouping() const {
        return "\1\2\3";
    }
};

int main() {
    const my_facet f(1);
    std::ios my_ios(nullptr);
    my_ios.imbue(std::locale{std::locale{}, new my_numpunct});

    long v                     = -1;
    const char str[]           = "+1_";
    std::ios_base::iostate err = std::ios_base::goodbit;
    const char* const iter     = f.get(std::begin(str), std::end(str), my_ios, err, v);
    assert(iter == std::end(str) - 1);
    assert(err == std::ios_base::failbit);
    assert(v == 1);
}