Producer Consumer C中的Segementation Fault C

Question

我試圖在C和線程中使用bounder緩衝來模擬生產者消費者問題。 也使用互斥和信號量。 預期的輸出是每次產品或消費時顯示緩衝區的狀態。 緩衝區大小固定爲10.最初，緩衝區項全部爲-1。當生產者生產一個項目時，該項目會替換-1。 第0項索引爲0，第1項索引爲1，依此類推.....無關緊要。 該程序詢問我們想要創建的生產者和消費者的數量。 生產工作正常....但不消耗。 線程1中出現分段錯誤。我不確定線程​​1是什麼。 我試圖用GDB多次調試....沒有任何希望。 //生產者消費者。

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

#define TRUE 1 

int buff_size=10,i; 
int buffer[25]; 

pthread_mutex_t mutex; 
sem_t full, empty; 

int counter = 0; 
int consume_count=0; //No of Consumers created 
int produce_count=0; //No of Producers created 

void initializeData() 
{ 
    sem_init(&full, 0, 0); 
    sem_init(&empty, 0, buff_size); 
    pthread_mutex_init(&mutex, NULL); 

} 

int insert_item(int counter) 
{ 
    if (counter < buff_size) { 
     buffer[counter] = counter; 
     counter++; 
     //produce_count++; 
     return 0; 
    } 

    else { 
     printf("\n[BUFFER FULL!]"); 
     return -1; 
    } 
} 

int remove_item() 
{ 
    printf("\n[GOING TO REMOVE AN ITEM]\n"); 

    if (buffer[counter-1] != -1) { 
     buffer[counter-1] = -1; 
     counter--; 
     //consume_count++; // Commented out... 

     return 0; 
    } 

    else { 
     printf("\n[EMPTY]\n"); 
     return -1; 
    } 
} 

void *producer(void *arg) 
{ 
    int RET = 0; 

    while(TRUE) { 
     sem_wait(&empty); 
     pthread_mutex_lock(&mutex); 

    RET = insert_item(counter); 

    if (RET){ 
     printf("\nProducer Sleeping...zzZZ\n"); 
     sleep(2); 
    } 

    pthread_mutex_unlock(&mutex); 
    sem_post(&full); 

    if(!RET) 
     printf("\n[ INSERTED ]\n"); 

    printf("\n"); 

    for(i=0; i < buff_size ;i++) 
     printf("[%d] ",buffer[i]); 

    printf("\n"); 
    sleep(3); 
    } // end of while... 


} 

void *consumer(void *arg) 
{ 
    int RET = 0; 

    while(TRUE) { 
    sem_wait(&full); 
    pthread_mutex_lock(&mutex); 

    RET = remove_item(buffer); 

    if (RET){ 
     printf("\nConsumer Sleeping\n"); 
     sleep(3); 
    } 

    pthread_mutex_unlock(&mutex); 
    sem_post(&empty); 

    if(!RET) { 
     printf("\nConsumed\n"); 
     printf("\n"); 
    } 

    for(i=0 ; i < buff_size ; i++) 
     printf("%4d",buffer[i]); 

    printf("\n"); 
    sleep(2); 
    } //end of while... 

} 

void main() 
{ 
    int   produce, consume; 
    pthread_t *prod;//thread ID 
    pthread_t *cons;//thread ID 

    printf("\nEnter the no of producers: "); 
    scanf("%d",&produce); 
    printf("\nEnter the no of consumers: "); 
    scanf("%d",&consume); 
    putchar('\n'); 

    for (i=0; i < buff_size; i++) 
     buffer[i] = -1; 

    for (i=0; i < buff_size; i++) 
     printf("[%d] ", buffer[i]); 

    printf("\n"); 

    initializeData(); 

    for (i = 0; i < produce; i++) 
     { 
      pthread_create(&prod[i], NULL, producer, NULL); 
      produce_count++; 
     } 

    for (i = 0; i < consume; i++) 
     { 

      pthread_create(&cons[i], NULL, consumer, NULL); 
      consume_count++; 
      printf("AAAAA"); 
     } 
    /*for (i = 0; i < produce; i++) 
     pthread_join(producer, NULL); 

     for (i = 0; i < consume; i++) 
      pthread_join(consumer, NULL);*/ 

printf("\n===============\n[ PRODUCED: %d ]", produce_count); 
printf("\n[ CONSUMED: %d ]\n==============", consume_count);  
} 

Answer 1

pthread_create(&prod[i], NULL, producer, NULL); 

在這個調用pthread_create將創建新的線程，並嘗試在督促返回線程ID [I] 但是：

pthread_t *prod;//thread ID 
pthread_t *cons;//thread ID 

這些uninitiaised指針，如果你想收集線程ID在他們中，您需要使用malloc分配內存給他們：

prod = malloc(sizeof(pthread_t) * produce); 
cons = malloc(sizeof(pthread_t) * consume); 

否則，pthread_create將存儲無效內存中的threadid，導致段錯誤