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//===----------------------------------------------------------------------===//
//
// 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.
//
//===----------------------------------------------------------------------===//
// <mutex>
// struct once_flag;
// template<class Callable, class ...Args>
// void call_once(once_flag& flag, Callable func, Args&&... args);
#include <mutex>
#include <thread>
#include <cassert>
typedef std::chrono::milliseconds ms;
std::once_flag flg0;
int init0_called = 0;
void init0()
{
std::this_thread::sleep_for(ms(250));
++init0_called;
}
void f0()
{
std::call_once(flg0, init0);
}
std::once_flag flg3;
int init3_called = 0;
int init3_completed = 0;
void init3()
{
++init3_called;
std::this_thread::sleep_for(ms(250));
if (init3_called == 1)
throw 1;
++init3_completed;
}
void f3()
{
try
{
std::call_once(flg3, init3);
}
catch (...)
{
}
}
#ifndef _LIBCPP_HAS_NO_VARIADICS
struct init1
{
static int called;
void operator()(int i) {called += i;}
};
int init1::called = 0;
std::once_flag flg1;
void f1()
{
std::call_once(flg1, init1(), 1);
}
struct init2
{
static int called;
void operator()(int i, int j) const {called += i + j;}
};
int init2::called = 0;
std::once_flag flg2;
void f2()
{
std::call_once(flg2, init2(), 2, 3);
std::call_once(flg2, init2(), 4, 5);
}
#endif // _LIBCPP_HAS_NO_VARIADICS
std::once_flag flg41;
std::once_flag flg42;
int init41_called = 0;
int init42_called = 0;
void init42();
void init41()
{
std::this_thread::sleep_for(ms(250));
++init41_called;
}
void init42()
{
std::this_thread::sleep_for(ms(250));
++init42_called;
}
void f41()
{
std::call_once(flg41, init41);
std::call_once(flg42, init42);
}
void f42()
{
std::call_once(flg42, init42);
std::call_once(flg41, init41);
}
#ifndef _LIBCPP_HAS_NO_VARIADICS
class MoveOnly
{
MoveOnly(const MoveOnly&);
public:
MoveOnly() {}
MoveOnly(MoveOnly&&) {}
void operator()(MoveOnly&&)
{
}
};
#endif
int main()
{
// check basic functionality
{
std::thread t0(f0);
std::thread t1(f0);
t0.join();
t1.join();
assert(init0_called == 1);
}
// check basic exception safety
{
std::thread t0(f3);
std::thread t1(f3);
t0.join();
t1.join();
assert(init3_called == 2);
assert(init3_completed == 1);
}
// check deadlock avoidance
{
std::thread t0(f41);
std::thread t1(f42);
t0.join();
t1.join();
assert(init41_called == 1);
assert(init42_called == 1);
}
#ifndef _LIBCPP_HAS_NO_VARIADICS
// check functors with 1 arg
{
std::thread t0(f1);
std::thread t1(f1);
t0.join();
t1.join();
assert(init1::called == 1);
}
// check functors with 2 args
{
std::thread t0(f2);
std::thread t1(f2);
t0.join();
t1.join();
assert(init2::called == 5);
}
{
std::once_flag f;
std::call_once(f, MoveOnly(), MoveOnly());
}
#endif // _LIBCPP_HAS_NO_VARIADICS
}
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