c++ - MacOS : libc++abi. dylib 上的线程:正在终止

Question

我有一个简单的程序来调用线程调用线程。我确定我显然遗漏了一些东西。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.

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

我正在互联网上搜索任何有用的信息，但不幸的是没有找到任何东西。

我的第二个代码是什么，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;
}

使用互斥量(仍然有问题):

#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“线程”时存在竞争条件。