生产者消费者问题：C语言指针类型不兼容及输出异常求助

问题背景 #

尝试用mutex、条件变量和pthreads实现生产者消费者模型。已参考相关方案将线程函数改为void* funcname(void *args)格式，但仍存在以下问题：

• pthread_create参数3指针类型不兼容警告
• 字符串溢出警告
• 程序输出不完整

编译警告与程序输出 #

main.c: In function ‘main’:
main.c:33:42: warning: passing argument 3 of ‘pthread_create’ from incompatible pointer type [-Wincompatible-pointer-types]
33 | pthread_create(&thread[i], NULL, producer, &thread_id[i]);
| ^~~~~~~~
| |
| void * (*)(int )
In file included from main.c:2:
/usr/include/pthread.h:200:15: note: expected ‘void * ()(void )’ but argument is of type ‘void * ()(int *)’
200 | void (__start_routine) (void ),
| ^~~~~~~~~~~~~~~~~
main.c:36:42: warning: passing argument 3 of ‘pthread_create’ from incompatible pointer type [-Wincompatible-pointer-types]
36 | pthread_create(&thread[i], NULL, consumer, &thread_id[i]);
| ^~~~~~~~
| |
| void * ()(int )
In file included from main.c:2:
/usr/include/pthread.h:200:15: note: expected ‘void * ()(void )’ but argument is of type ‘void * ()(int *)’
200 | void (__start_routine) (void *),
| ^~~~~~~~~~~~~~~~~
main.c:30:5: warning: ‘__builtin_memcpy’ writing 7 bytes into a region of size 6 overflows the destination [-Wstringop-overflow=]
30 | strcpy(source, "abcdef");
| ^~~~~~~~~~~~~~~~~~~~~~~~
1 is produced abcdef in buffer
1 is consuming from buffer
0 is consuming from buffer

完整代码 #

#include <stdio.h>
#include <pthread.h>
#include <semaphore.h>
#include <stdlib.h>
#include <string.h>
#define MAX 10
#define BUFLEN 6
#define NUMTHREAD 2

void* consumer(int *id);
void* producer(int *id);

char buffer[BUFLEN];
char source[BUFLEN];
int pCount = 0;
int cCount = 0;
int buflen;

pthread_mutex_t count_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t nonEmpty = PTHREAD_COND_INITIALIZER;
pthread_cond_t full = PTHREAD_COND_INITIALIZER;
int thread_id[NUMTHREAD] = {0, 1};
int i = 0;
int j = 0;

int main()
{
    int i;
    pthread_t thread[NUMTHREAD];
    strcpy(source, "abcdef");
    buflen = strlen(source);
    for (i = 0; i < NUMTHREAD; i++){
        pthread_create(&thread[i], NULL, producer, &thread_id[i]);
    }
    for (i = 0; i < NUMTHREAD; i++){
        pthread_create(&thread[i], NULL, consumer, &thread_id[i]);
    }
    for (i = 0; i < NUMTHREAD; i++){
        pthread_join(thread[i], NULL);
    }
    printf("\n");
}

void *producer(int *id)
{
    int i;
    pthread_mutex_lock(&count_mutex);
    while (pCount == MAX)
    {
        printf("Producer %d is waiting for empty buffer\n", *id);
        pthread_cond_wait(&nonEmpty, &count_mutex);
    }
    for (i = 0; i < BUFLEN; i++)
    {
        buffer[i] = source[i];
    }
    pCount++;
    printf("%d is produced %s in buffer\n", *id, source);
    pthread_cond_signal(&full);
    pthread_mutex_unlock(&count_mutex);
}

void *consumer(int *id)
{
    int i;
    pthread_mutex_lock(&count_mutex);
    while (cCount == MAX)
    {
        printf("Consumer %d is waiting for full buffer\n", *id);
        pthread_cond_wait(&full, &count_mutex);
    }
    for (i = 0; i < BUFLEN; i++)
    {
        buffer[i] = '\0';
    }
    cCount++;
    printf("%d is consuming %s from buffer\n", *id, buffer);
    pthread_cond_signal(&nonEmpty);
    pthread_mutex_unlock(&count_mutex);
}

内容的提问来源于stack exchange，提问作者EmployedSlaveStudent