POSIX线程和信号量

Question

我无法调试以下程序,因为我家里没有linux.我无法执行该程序,但在实验室会话中编译程序时,我遇到了两个错误.谁能帮我吗？如果有人能够在调试后执行该程序,请发布输出.

代码如下:

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <semaphore.h>
#define BUFFER_SIZE 10
sem_t empty;
sem_t full;
pthread_mutex_t mutex;

int buffer[BUFFER_SIZE];

pthread_t ptid,ctid;
pthread_attr_t attr;

void *producer(void *param);
void *consumer(void *param);

int counter;
int main()
{

  init();
  pthread_create(&ptid, &attr, producer, NULL);
  pthread_create(&ctid, &attr, consumer, NULL);
  pthread_join(ptid,NULL);
  pthread_join(ctid,NULL);

  return 0;
}

void init()
{
  pthread_mutex_init(&mutex, NULL);
  pthread_attr_init(&attr);
  sem_init(&full, 0, 0);
  sem_init(&empty, 0, BUFFER_SIZE);
  counter = 0;
  for(int j=0;j<BUFFER_SIZE;j++)
  {  buffer[j] = 0;}
}

void *producer(void *param)
{
int item;
  while(1)
  {
    item=item+1;
    sem_wait(&empty);
    pthread_mutex_lock(&mutex);

    if(insert_item(item))
    {
      perror("Producer error.");
      return 1;
    }
    else
    {
      printf("Producer produced %d\n", item);
    }

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

void *consumer(void *param)
{
  int item;
  while(1)
  {
sleep(5);
    sem_wait(&full);
    pthread_mutex_lock(&mutex);
    if(remove_item(item))
    {
      perror( "Consumer error.");
    }
    else
    {
      printf("Consumer consumed %d\n", item);
    }

    pthread_mutex_unlock(&mutex);
    sem_post(&empty);
  }
}
int insert_item(int item)
{
  if(counter < BUFFER_SIZE)
  {
    buffer[counter] = item;
    counter++;
    return 0;
  }
  else
    return -1;

}

int remove_item(int item)
{
  if(counter > 0)
  {
    item = buffer[(counter-1)];
    counter--;
    return ;
  }
  else
    return -1;

}

在进行更改和更正后,我现在获得以下输出,这不是所需的输出.......

[root@localhost sree58]# gcc producerconsumer.c -lpthread -lrt
producerconsumer.c: In function ‘producer’:
producerconsumer.c:54: warning: return makes pointer from integer without a cast
[root@localhost sree58]# ./a.out
Producer produced 1804289383
Producer produced 846930886
Producer produced 1681692777
Producer produced 1714636915
Producer produced 1957747793
Producer produced 424238335
Producer produced 719885386
Producer produced 1649760492
Producer produced 596516649
Producer produced 1189641421
Consumer error.: Success
Producer produced 1025202362
Consumer error.: Illegal seek
Producer produced 1350490027
Consumer error.: Illegal seek
Producer produced 783368690
Consumer error.: Illegal seek
Producer produced 1102520059
Consumer error.: Illegal seek
Producer produced 2044897763
Consumer error.: Illegal seek
Producer produced 1967513926
Consumer error.: Illegal seek
Producer produced 1365180540
Consumer error.: Illegal seek
Producer produced 1540383426
Consumer error.: Illegal seek
Producer produced 304089172
Consumer error.: Illegal seek
Producer produced 1303455736
Consumer error.: Illegal seek
Producer produced 35005211
Consumer error.: Illegal seek
Producer produced 521595368
Consumer error.: Illegal seek
Producer produced 294702567
Consumer error.: Illegal seek
Producer produced 1726956429

请有人指导我......

Answer 1

首先,让我们解决这个问题(帮助自己的工具): since i don't have linux at home

转到Oracle的站点并下载VirtualBox,然后转到您最喜欢的Linux发行版的站点并下载.iso它的图像(例如,如果您感觉Minty,您可以在这里获得iso )

然后你可以按照说明在虚拟机中设置和"安装"iso瞧!你家里有Linux.;)

其次,我将解决这个问题: i got two errors

真？你怎么编译这个？运行代码时,我看到一堆警告和一个错误gcc -Wall.一个错误告诉您如何在消息中修复它:

38:3: error: ‘for’ loop initial declarations are only allowed in C99 mode
38:3: note: use option -std=c99 or -std=gnu99 to compile your code

添加该命令gcc -Wall -std=c99,现在您看到由于缺少pthread库而导致的未定义引用:

undefined reference to `pthread_create'

通过链接在以下内容中修复:

gcc -Wall -std=c99 <yourfile>.c -lpthread

现在你所拥有的是一堆(重要的)警告:

In function ‘main’:
22:3: warning: implicit declaration of function ‘init’ [-Wimplicit-function-declaration]
At top level:
31:6: warning: conflicting types for ‘init’ [enabled by default]
22:3: note: previous implicit declaration of ‘init’ was here

In function ‘producer’:
51:5: warning: implicit declaration of function ‘insert_item’ [-Wimplicit-function-declaration]
54:7: warning: return makes pointer from integer without a cast [enabled by default]

In function ‘consumer’:
71:1: warning: implicit declaration of function ‘sleep’ [-Wimplicit-function-declaration]
74:5: warning: implicit declaration of function ‘remove_item’ [-Wimplicit-function-declaration]

In function ‘remove_item’:
106:5: warning: ‘return’ with no value, in function returning non-void [enabled by default]

In function ‘consumer’:
74:19: warning: ‘item’ is used uninitialized in this function [-Wuninitialized]