1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// <ostream>
10
11// template <class charT, class traits = char_traits<charT> >
12// class basic_ostream;
13
14// basic_ostream<charT,traits>& operator<<(basic_ios<charT,traits>&
15// (*pf)(basic_ios<charT,traits>&));
16
17#include <ostream>
18#include <cassert>
19
20#include "test_macros.h"
21
22template <class CharT>
23class testbuf
24 : public std::basic_streambuf<CharT>
25{
26 typedef std::basic_streambuf<CharT> base;
27 std::basic_string<CharT> str_;
28public:
29 testbuf()
30 {
31 }
32
33 std::basic_string<CharT> str() const
34 {return std::basic_string<CharT>(base::pbase(), base::pptr());}
35
36protected:
37
38 virtual typename base::int_type
39 overflow(typename base::int_type ch = base::traits_type::eof())
40 {
41 if (ch != base::traits_type::eof())
42 {
43 int n = static_cast<int>(str_.size());
44 str_.push_back(static_cast<CharT>(ch));
45 str_.resize(str_.capacity());
46 base::setp(const_cast<CharT*>(str_.data()),
47 const_cast<CharT*>(str_.data() + str_.size()));
48 base::pbump(n+1);
49 }
50 return ch;
51 }
52};
53
54template <class CharT>
55std::basic_ios<CharT>&
56f(std::basic_ios<CharT>& os)
57{
58 std::uppercase(base&: os);
59 return os;
60}
61
62int main(int, char**)
63{
64 {
65 testbuf<char> sb;
66 std::ostream os(&sb);
67 assert(!(os.flags() & std::ios_base::uppercase));
68 os << f;
69 assert( (os.flags() & std::ios_base::uppercase));
70 }
71
72 return 0;
73}
74

source code of libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters/basic_ios.pass.cpp