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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// UNSUPPORTED: libcpp-has-no-stdin, libcpp-has-no-stdout
// Make sure that the iostreams are initialized before everything else.
// This has been an issue when statically linking libc++ in some contexts.
// See for details.
// This test works by checking that std::{cin,cout,cerr} is the same in a
// static object constructor and in the main function. It dumps the memory of
// each stream in the static object constructor and compares it with the memory
// in the main function.
// The assumption is that if there are no uses of the stream object (such as
// construction), then its memory must be the same. In the case where the test
// "fails" and we are actually accessing an uninitialized object when we perform
// the memcpy, the behavior is technically undefined (so the test could still
// pass).
#include <cassert>
#include <cstring>
#include <iostream>
struct Checker {
char *cerr_mem_dump;
char *cin_mem_dump;
char *cout_mem_dump;
char *clog_mem_dump;
char *wcerr_mem_dump;
char *wcin_mem_dump;
char *wcout_mem_dump;
char *wclog_mem_dump;
: cerr_mem_dump(new char[sizeof(std::cerr)])
, cin_mem_dump(new char[sizeof(std::cin)])
, cout_mem_dump(new char[sizeof(std::cout)])
, clog_mem_dump(new char[sizeof(std::clog)])
, wcerr_mem_dump(new char[sizeof(std::wcerr)])
, wcin_mem_dump(new char[sizeof(std::wcin)])
, wcout_mem_dump(new char[sizeof(std::wcout)])
, wclog_mem_dump(new char[sizeof(std::wclog)])
std::memcpy(cerr_mem_dump, (char*)&std::cerr, sizeof(std::cerr));
std::memcpy(cin_mem_dump, (char*)&std::cin, sizeof(std::cin));
std::memcpy(cout_mem_dump, (char*)&std::cout, sizeof(std::cout));
std::memcpy(clog_mem_dump, (char*)&std::clog, sizeof(std::clog));
std::memcpy(wcerr_mem_dump, (char*)&std::wcerr, sizeof(std::wcerr));
std::memcpy(wcin_mem_dump, (char*)&std::wcin, sizeof(std::wcin));
std::memcpy(wcout_mem_dump, (char*)&std::wcout, sizeof(std::wcout));
std::memcpy(wclog_mem_dump, (char*)&std::wclog, sizeof(std::wclog));
~Checker() {
delete[] cerr_mem_dump;
delete[] cin_mem_dump;
delete[] cout_mem_dump;
delete[] clog_mem_dump;
delete[] wcerr_mem_dump;
delete[] wcin_mem_dump;
delete[] wcout_mem_dump;
delete[] wclog_mem_dump;
static Checker check;
int main(int, char**) {
assert(std::memcmp(check.cerr_mem_dump, (char const*)&std::cerr, sizeof(std::cerr)) == 0);
assert(std::memcmp(check.cin_mem_dump, (char const*)&std::cin, sizeof(std::cin)) == 0);
assert(std::memcmp(check.cout_mem_dump, (char const*)&std::cout, sizeof(std::cout)) == 0);
assert(std::memcmp(check.clog_mem_dump, (char const*)&std::clog, sizeof(std::clog)) == 0);
assert(std::memcmp(check.wcerr_mem_dump, (char const*)&std::wcerr, sizeof(std::wcerr)) == 0);
assert(std::memcmp(check.wcin_mem_dump, (char const*)&std::wcin, sizeof(std::wcin)) == 0);
assert(std::memcmp(check.wcout_mem_dump, (char const*)&std::wcout, sizeof(std::wcout)) == 0);
assert(std::memcmp(check.wclog_mem_dump, (char const*)&std::wclog, sizeof(std::wclog)) == 0);
return 0;