libcxx/test/std/input.output/iostream.format/input.streams/istream.formatted/istream_extractors/basic_ios.pass.cpp

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// <istream>

// template <class charT, class traits = char_traits<charT> >
//   class basic_istream;

// basic_istream<charT,traits>& operator>>(basic_ios<charT,traits>&
//                                         (*pf)(basic_ios<charT,traits>&));

#include <istream>
#include <cassert>

int f_called = 0;

template <class CharT>
std::basic_ios<CharT>&
f(std::basic_ios<CharT>& is)
{
    ++f_called;
    return is;
}

int main()
{
    {
        std::istream is((std::streambuf*)0);
        is >> f;
        assert(f_called == 1);
    }
}