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::sentry;
13
14// explicit sentry(basic_ostream<charT,traits>& os);
15
16#include <ostream>
17#include <cassert>
18
19#include "test_macros.h"
20
21int sync_called = 0;
22
23template <class CharT>
24struct testbuf1
25 : public std::basic_streambuf<CharT>
26{
27 testbuf1() {}
28
29protected:
30
31 int virtual sync()
32 {
33 ++sync_called;
34 return 1;
35 }
36};
37
38int main(int, char**)
39{
40 {
41 std::ostream os((std::streambuf*)0);
42 std::ostream::sentry s(os);
43 assert(!bool(s));
44 }
45 {
46 testbuf1<char> sb;
47 std::ostream os(&sb);
48 std::ostream::sentry s(os);
49 assert(bool(s));
50 }
51 {
52 testbuf1<char> sb;
53 std::ostream os(&sb);
54 testbuf1<char> sb2;
55 std::ostream os2(&sb2);
56 os.tie(tiestr: &os2);
57 assert(sync_called == 0);
58 std::ostream::sentry s(os);
59 assert(bool(s));
60 assert(sync_called == 1);
61 }
62
63 return 0;
64}
65

source code of libcxx/test/std/input.output/iostream.format/output.streams/ostream_sentry/construct.pass.cpp