经典同步问题linux下的C实现：生产者-消费者问题，读者-写者问题，哲学家问题

1.生产者-消费者问题

/*===============================================================

 * File Name : producerConsumerProblem.c
 * Creation Date : 2013-04-11
 * Last Modified : 2013年04月11日 星期四 20时53分13秒
 * Purpose :test linux semaphore usage

================================================================*/
#include <stdio.h>
#include <sys/types.h>
#include <semaphore.h>
#include <pthread.h>
#include <stdlib.h>

void *producer_handler(void *ptr);
void *consumer_handler(void *ptr);

sem_t mutex,blank,fill;
int *buffer;
int in=0,out=0,buffer_size=10;

void main()
{
	if((buffer=(int *)malloc(buffer_size*sizeof(int)))==NULL)
		printf("can't allocate memroy on heap\n");
	sem_init(&mutex,0,1);
	sem_init(&blank,0,buffer_size);
	sem_init(&fill,0,0);

	int err;
	pthread_t producer,consumer;
	err=pthread_create(&producer,NULL,producer_handler,NULL);
	if(err!=0)
		err_quit("can't crea