使线程循环5次;pthreads、互斥和信号量

问题是,在main结束时,我称之为sleep(2)。这还不够所有线程打印输出的时间。我也没有将正确的索引传递给add_item和remove_item函数。此外,我需要一个用于所有线程的join命令,而不是sleep命令,join命令确保所有线程在程序退出之前完成。这是更新和更正的代码。希望这能帮助到尝试做类似事情的人!

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <semaphore.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <sys/utsname.h>

// Symbolic Constants
#define NUM_THREADS 4
#define BUFFER_SIZE 10

// Semaphore and Mutex lock
sem_t cEmpty;
sem_t cFull;
pthread_mutex_t mutex;

// Threads
pthread_t tid[NUM_THREADS]; //Thread ID
pthread_t tid2[NUM_THREADS]; //Thread ID
pthread_attr_t attr; //Thread attributes

//prototypes
void *producer(void *param);
void *consumer(void *param);
int insert_item(long threadID);
int remove_item(long threadID);
void init();

//Progress Counter and Thread IDs
int counter=0;

int main()
{
  //Variables
  long c1;

  //Perform initialization
  init();

  //Create the producer threads
  for(c1=0; c1<NUM_THREADS; c1++)
  {
    pthread_create(&tid[c1], &attr, producer, (void *)c1);
    pthread_create(&tid2[c1], &attr, consumer, (void *)c1);
  }

  //Ending it
  for(c1=0; c1<NUM_THREADS; c1++)
  {
    pthread_join(tid[c1], NULL);
    pthread_join(tid2[c1],NULL);
  }

  printf("All threads are done.\n");

  //Destroy the mutex and semaphors
  pthread_mutex_destroy(&mutex);
  sem_destroy(&cEmpty);
  sem_destroy(&cFull);

  printf("Resources cleaned up.\n");

  exit(0);
}

//This function performs initialization
void init()
{
  pthread_mutex_init(&mutex, NULL); //Initialize mutex lock
  pthread_attr_init(&attr); //Initialize pthread attributes to default
  sem_init(&cFull, 0, 0); //Initialize full semaphore
  sem_init(&cEmpty, 0, BUFFER_SIZE); //Initialize empty semaphore
  counter = 0; //Initialize global counter
}

//This function creates the producer thread
void *producer(void *param)
{
  long index = (long)param;

  for(int x = 0; x<5; x++)
  {
    sleep(1);

    sem_wait(&cEmpty); //Lock empty semaphore if not zero
    pthread_mutex_lock(&mutex);

    //check to see if item inserted correctly; print error on fail
    if(insert_item(index))
    {
      fprintf(stderr, "Producer error.");
    }

    pthread_mutex_unlock(&mutex);
    sem_post(&cFull); //Increment semaphore for # of full
  }
pthread_exit(NULL);
return 0;
}

//This function created the consumer thread
void *consumer(void *param)
{
  long index = (long)param;

  for(int x = 0; x<5; x++)
  {
    sleep(1);

    sem_wait(&cFull); //Lock empty semaphore if not zero
    pthread_mutex_lock(&mutex);

    //print error if cookie not decremented correctly
    if(remove_item(index))
    {
      fprintf(stderr, "Consumer error.");
    }

    pthread_mutex_unlock(&mutex);
    sem_post(&cEmpty); //Increments semaphore for # of empty
  }
pthread_exit(NULL);
return 0;
}
//Insert item function to increment the cookie count and print thread message
int insert_item(long threadID)
{
  if(counter < BUFFER_SIZE) //Buffer has space
  {
    counter++;
    printf("Producer %ld inserted a cookie. Total:%d\n", threadID, counter);
    return 0;
  }
  else //Buffer full
  {
    return -1;
  }
}

//Remove item function to decrement the cookie count and print thread message
int remove_item(long threadID)
{
  if(counter > 0) //Buffer has something in it
  {
    counter--;
    printf("Consumer %ld removed a cookie. Total:%d\n", threadID, counter);
    return 0;
  }
  else //Buffer empty
  {
    return -1;
  }
}