Question

我有简单的程序来调用线程调用线程。我确定我明显遗漏了一些东西。下面是代码：

#include <iostream>
#include <vector>
#include <thread>
#include <unistd.h>

using namespace std;

vector<thread> threads;

void Next(int amount) {
for(int i = 0; i < amount; i++) threads.push_back(thread(Next,amount-1));
}

int main(int argc, char **argv) {
int amount = 2;

for(int i = 0; i < amount; i++) threads.push_back(thread(Next,amount-1));

cout << threads.size() << endl;
for (auto& th : threads) {
    if (th.joinable()) {
        th.join();
    }
}

return 0;
}

输出不同，例如：

1

2

2
libc++abi.dylib: terminating
Abort trap: 6

3

2
libc++abi.dylib: terminating with uncaught exception of type std::__1::system_error: thread::join failed: No such process
Abort trap: 6

我在互联网上搜索任何有用的信息，但遗憾的是没有找到任何信息。

我的第二个代码是什么工作，但我写得很好？

#include <iostream>
#include <vector>
#include <thread>
#include <unistd.h>

using namespace std;

void Next(int amount) {
vector<thread> threads;

for(int i = 0; i < amount; i++) threads.push_back(thread(Next,amount-1));

cout << threads.size() << endl;
    for (auto& th : threads) {
        if (th.joinable()) {
            th.join();
        }
    }
}

int main(int argc, char **argv) {
int amount = 2;

vector<thread> threads;

for(int i = 0; i < amount; i++) threads.push_back(thread(Next,amount-1));

cout << threads.size() << endl;
for (auto& th : threads) {
    if (th.joinable()) {
        th.join();
    }
}

return 0;
}

使用互斥锁（仍有问题）：

#include <iostream>
#include <vector>
#include <thread>
#include <unistd.h>
#include <mutex>

using namespace std;

mutex mtx;
vector <thread> threads;

using namespace std;

void Next(int amount) {
for(int i = 0; i < amount; i++) {
    mtx.lock();
    threads.push_back(thread(Next,amount-1));
    mtx.unlock();
}
}

int main(int argc, char **argv) {
int amount = 2;

for(int i = 0; i < amount; i++) {
    mtx.lock();
    threads.push_back(thread(Next,amount-1));
    mtx.unlock();
}

cout << threads.size() << endl;

for (auto& th : threads) {
    if (th.joinable()) {
        th.join();
    }
}

return 0;
}

Answer 1

您在访问vector＆＃39;线程时遇到竞争条件。

MacOS上的线程：libc ++ abi.dylib：终止

1 个答案: