C 传递父线程 ID

Posted 2023-02-14

【中文标题】C 传递父线程 ID

【英文标题】：C Pass the Parent-Thread ID

【发布时间】：2021-12-31 22:28:21

【问题描述】：

如何传递父 ID 并在第二个 printf() 中打印出来？？

第一行示例：

我 1 岁，我有 4 个孩子（dren）我的父母 ??? 我 2 岁，我有 2 个孩子（dren）我的父母？？？

预期： 我是 1，我有 4 个孩子（dren）我的父母 0 我 2 岁，我有 2 个孩子（dren）我的父母 1

#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>


typedef struct parameter 
    unsigned int amount_children;
    int thread_number;
 parameter_t;

#define MAX_CHILDTHREADS 16
#define N_ZERO 4
unsigned int countthreads = 0;
unsigned int divisor = 2;

pthread_mutex_t count_mutex;
pthread_attr_t attr;



void * tree(void*);

int main()
    pthread_t th;
    pthread_attr_init(&attr);
    pthread_mutex_init(&count_mutex,NULL);
    //countthreads++;
    parameter_t params =  N_ZERO*divisor, countthreads;
    //pthread_create(&th,&attr,&tree,(void*)&params);
    tree(&params);
    printf("Totalamount of created Threads %d \n", countthreads);



void * tree(void * args)
    parameter_t* paramArgs = (parameter_t*) args;
    int N_threads = paramArgs->amount_children / divisor; // anzahl der theoretisch benötogten Threads
    int amount_childthreads = (N_threads <= MAX_CHILDTHREADS) ? N_threads : MAX_CHILDTHREADS;
    pthread_t threads[amount_childthreads];
    printf("I am %d and and I have %d child(dren), my parent is ???\n", paramArgs->thread_number, 
    amount_childthreads);

    parameter_t param[ amount_childthreads ];
    for(int i = 0; i < amount_childthreads; i++)
        pthread_mutex_lock( &count_mutex );
        int j = ++countthreads;
        pthread_mutex_unlock( &count_mutex );

        param[i].amount_children = N_threads;
        param[i].thread_number = j;
        pthread_create( threads+i, &attr, &tree, param + i );
    

    for(int i = 0; i < amount_childthreads; i++)
        pthread_join(threads[i],NULL);
    
    printf("I am %d and done\n",paramArgs->thread_number);

【参考方案1】：

您可以使用 POSIX getppid() 函数来获取父进程的 PID。

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