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// Make sure that the iostreams are initialized before everything else.
10// This has been an issue when statically linking libc++ in some contexts.
11// See https://llvm.org/PR28954 for details.
12//
13// This test works by checking that std::{cin,cout,cerr} is the same in a
14// static object constructor and in the main function. It dumps the memory of
15// each stream in the static object constructor and compares it with the memory
16// in the main function.
17//
18// The assumption is that if there are no uses of the stream object (such as
19// construction), then its memory must be the same. In the case where the test
20// "fails" and we are actually accessing an uninitialized object when we perform
21// the memcpy, the behavior is technically undefined (so the test could still
22// pass).
23
24#include <cassert>
25#include <cstring>
26#include <iostream>
27
28#include "test_macros.h"
29
30struct Checker {
31 char *cerr_mem_dump;
32 char *cin_mem_dump;
33 char *cout_mem_dump;
34 char *clog_mem_dump;
35
36 Checker()
37 : cerr_mem_dump(new char[sizeof(std::cerr)])
38 , cin_mem_dump(new char[sizeof(std::cin)])
39 , cout_mem_dump(new char[sizeof(std::cout)])
40 , clog_mem_dump(new char[sizeof(std::clog)])
41 {
42 std::memcpy(dest: cerr_mem_dump, src: (char*)&std::cerr, n: sizeof(std::cerr));
43 std::memcpy(dest: cin_mem_dump, src: (char*)&std::cin, n: sizeof(std::cin));
44 std::memcpy(dest: cout_mem_dump, src: (char*)&std::cout, n: sizeof(std::cout));
45 std::memcpy(dest: clog_mem_dump, src: (char*)&std::clog, n: sizeof(std::clog));
46 }
47
48 ~Checker() {
49 delete[] cerr_mem_dump;
50 delete[] cin_mem_dump;
51 delete[] cout_mem_dump;
52 delete[] clog_mem_dump;
53 }
54};
55static Checker check;
56
57#ifndef TEST_HAS_NO_WIDE_CHARACTERS
58struct WideChecker {
59 char *wcerr_mem_dump;
60 char *wcin_mem_dump;
61 char *wcout_mem_dump;
62 char *wclog_mem_dump;
63
64 WideChecker()
65 : wcerr_mem_dump(new char[sizeof(std::wcerr)])
66 , wcin_mem_dump(new char[sizeof(std::wcin)])
67 , wcout_mem_dump(new char[sizeof(std::wcout)])
68 , wclog_mem_dump(new char[sizeof(std::wclog)])
69 {
70 std::memcpy(dest: wcerr_mem_dump, src: (char*)&std::wcerr, n: sizeof(std::wcerr));
71 std::memcpy(dest: wcin_mem_dump, src: (char*)&std::wcin, n: sizeof(std::wcin));
72 std::memcpy(dest: wcout_mem_dump, src: (char*)&std::wcout, n: sizeof(std::wcout));
73 std::memcpy(dest: wclog_mem_dump, src: (char*)&std::wclog, n: sizeof(std::wclog));
74 }
75
76 ~WideChecker() {
77 delete[] wcerr_mem_dump;
78 delete[] wcin_mem_dump;
79 delete[] wcout_mem_dump;
80 delete[] wclog_mem_dump;
81 }
82};
83
84static WideChecker wide_check;
85#endif
86
87int main(int, char**) {
88 assert(std::memcmp(check.cerr_mem_dump, (char const*)&std::cerr, sizeof(std::cerr)) == 0);
89 assert(std::memcmp(check.cin_mem_dump, (char const*)&std::cin, sizeof(std::cin)) == 0);
90 assert(std::memcmp(check.cout_mem_dump, (char const*)&std::cout, sizeof(std::cout)) == 0);
91 assert(std::memcmp(check.clog_mem_dump, (char const*)&std::clog, sizeof(std::clog)) == 0);
92
93#ifndef TEST_HAS_NO_WIDE_CHARACTERS
94 assert(std::memcmp(wide_check.wcerr_mem_dump, (char const*)&std::wcerr, sizeof(std::wcerr)) == 0);
95 assert(std::memcmp(wide_check.wcin_mem_dump, (char const*)&std::wcin, sizeof(std::wcin)) == 0);
96 assert(std::memcmp(wide_check.wcout_mem_dump, (char const*)&std::wcout, sizeof(std::wcout)) == 0);
97 assert(std::memcmp(wide_check.wclog_mem_dump, (char const*)&std::wclog, sizeof(std::wclog)) == 0);
98#endif
99 return 0;
100}
101

source code of libcxx/test/std/input.output/iostream.objects/init.pass.cpp