pthread（分割錯誤）

Question

我是韓國人，我不擅長英語，但如果你給我評價那裏
我會很高興，並會嘗試去理解它。

我創建了例如10個線程，並在創建後嘗試加入它們並返回值。
但是，當我加入最後一個線程時，出現了分段錯誤。

結果出來這樣的..

Before Thread 1 create 
After Thread 1 create 
Before Thread 0 create 
After Thread 0 create 
Before Thread 1 join 
After Thread 1 join 
Before Thread 0 join 
Segmentation Fault(core dumped) 

當我創建4個線程就好像

Before Thread 3 create 
After Thread 3 create 
Before Thread 2 create 
After Thread 2 create 
Before Thread 1 create 
After Thread 1 create 
Before Thread 0 create 
After Thread 0 create 
Before Thread 3 join 
After Thread 3 join 
Before Thread 2 join 
After Thread 2 join 
Before Thread 1 join 
After Thread 1 join 
Before Thread 0 join 
Segmentation Fault(core dumped) 

我似乎無法找到原因。

#include <stdio.h> 
#include <stdlib.h> 
#include <pthread.h> 
#include <unistd.h> 

pthread_mutex_t mutex_lock; 

struct arg_struct { 
     int a; 
     int b; 
}; 

void *t_function(void *data) { 
     pthread_mutex_lock(&mutex_lock); 

     struct arg_struct *arg = (struct arg_struct *)data; 
     long int s; 

     s = arg->a; 

     pthread_mutex_unlock(&mutex_lock); 

     return (void **)s; 
} 

int main() 
{ 
     int i; 

     pthread_t p_thread[2]; 
     int thr_id; 
     int status; 

     struct arg_struct arg[2]; 

     for(i = 1; i >= 0; i--) { 
       arg[i].a = i; 
       arg[i].b = i; 
     } 

     pthread_mutex_init(&mutex_lock, NULL); 

     for(i = 1; i >= 0; i--) { 
       printf("Before Thread %d create\n", i); 
       thr_id = pthread_create(&p_thread[i],NULL, t_function, (void *)&arg[i]); 
       printf("After Thread %d create\n", i); 
       usleep(1000); 
     } 

     int temp[2]; 

     for(i = 1; i >= 0; i--) { 
       printf("Before Thread %d join\n", i); 
       pthread_join(p_thread[i], (void**)&status); 
       printf("After Thread %d join\n", i); 
       temp[i] = status; 
     }i 

     printf("%d%d", temp[1], temp[0]); 

     pthread_mutex_destroy(&mutex_lock); 

     return 0; 
} 

Answer 1

pthread_t p_thread[2]; 
    struct arg_struct arg[2]; 
    int temp[2]; 

你只分配空間，這裏有兩個要素，因此，如果您推出超過2個線程，你會跑出數組的結尾，並可能崩潰或損壞堆棧。

此外：

  pthread_join(p_thread[i], (void**)&status); 

status爲int，而不是一個void *;嘗試這將嘗試在int中存儲void *。在許多64位平臺上，這也會溢出（因爲void *將是8字節，而int是4）。使status a void *，並停止試圖擺脫這樣的編譯器錯誤。他們是有原因的錯誤。