Question

我试图理解为什么当我尝试在写入文件时使用线程。它会在一段时间后停止写入此文件。我理解线程但不太深入。以下是我使用的示例代码：

#include <chrono>
#include <iostream>
#include <stdlib.h>
# include <stdio.h>
#include <thread>
#include <unistd.h>
// http://www.bogotobogo.com/cplusplus/cpptut.php
using namespace std;

float counter = 0;

void *call_from_thread(void *) {
        FILE *f = fopen64("results_text.txt", "a");
        if (f == NULL)
            {
                printf("Error opening file!\n");
                exit(1);
            }    

        fprintf(f, " this is some text to be written in the file to see the max size of writting using threads \n");

        fclose(f);    
        printf("|I am in the thread \n" );    
        usleep(50);    
        return NULL;
}


int main() {    
    while (true) {    
        std::thread t([] {call_from_thread(NULL);});

        counter++;
        // To let the main thread continue running and detach from the last created thread, the thread must have finished execution before recalling it once again.
        // if the thread sleeps more than the main thread, then after some time the program will run out of resources and the program crash
        // to test this case: try to put 5000 in the usleep inside the thread
        t.detach();
        // Will make the main thread wait for the thread till it finishes
        //t.join();

        printf("|I am alive %f \n", counter);    
        usleep(100);
    }

return 0;
}

我正在使用“detach”功能来保存我计算机上的资源，但在运行一段时间后仍然出现以下错误：

 terminate called after throwing an instance of 'std::system_error'
  what():  Resource temporarily unavailable

非常感谢任何帮助。

资源在C ++多线程中不可用

0 个答案: