静态分配互斥量与动态分配互斥量的区别和实例分析

1）、静态分配互斥量：

#include "stdio.h"#include <stdlib.h>#include <pthread.h>#define N_CONSUMER 3 //消费者数量#define N_PRODUCER 2 //生产者数量#define C_SLEEP 1 //控制 consumer 消费的节奏#define P_SLEEP 1 //控制 producer 生产的节奏pthread_t ctid[N_CONSUMER];//消费者线程数组pthread_t ptid[N_PRODUCER];//生产者线程数组pthread_cond_t notFull,notEmpty;//定义条件变量，notFull缓冲区不满;notEmpty缓冲区不空pthread_mutex_t buf = PTHREAD_MUTEX_INITIALIZER;//静态分配互斥量，用于锁住缓冲区int begin = 0,end = 0, cnt = 0, max = 4;//从 begin 到 end(不含end) 代表产品，cnt 代表产品数量，max 代                                          表库房的容量，即最多生产多少产品void * consumer(void * pidx)//consumer thread idx{        printf("consumer thread id %d\n",*((int *)pidx));        while(1)        { pthread_mutex_lock(&buf);                while(cnt == 0){//当缓冲区空时                        pthread_cond_wait(¬Empty,&buf);//阻塞并等待不空的信号                }                printf("consume %d\n",begin);                begin = (begin+1)%max;                cnt--;                pthread_mutex_unlock(&buf);                sleep(C_SLEEP);                pthread_cond_signal(¬Full);        }        pthread_exit((void *)0);}void * producer(void * pidx)//producer thread idx{        printf("producer thread id %d\n",*((int *)pidx));        while(1)        {                pthread_mutex_lock(&buf);                while(cnt == max){//当缓冲区满时                        pthread_cond_wait(¬Full,&buf);                } pthread_mutex_lock(&buf);                while(cnt == 0){//当缓冲区空时                        pthread_cond_wait(¬Empty,&buf);//阻塞并等待不空的信号                }                printf("consume %d\n",begin);                begin = (begin+1)%max;                cnt--;                pthread_mutex_unlock(&buf);                sleep(C_SLEEP);                pthread_cond_signal(¬Full);        }        pthread_exit((void *)0);}void * producer(void * pidx)//producer thread idx{        printf("producer thread id %d\n",*((int *)pidx));        while(1)        {                pthread_mutex_lock(&buf);                while(cnt == max){//当缓冲区满时                        pthread_cond_wait(¬Full,&buf);                }int main(){        int i  = 0;        for(i = 0; i < N_CONSUMER; i++)        {                int * j = (int *) malloc(sizeof(int));                *j = i;                if(pthread_create(&ctid[i],NULL,consumer,j) != 0)                {                        perror("create consumer failed\n");                        exit(1);                }        }        for(i = 0; i < N_PRODUCER; i++)        {                int * j = (int *) malloc(sizeof(int));                *j = i;                if(pthread_create(&ptid[i],NULL,producer,j) != 0)                {                        perror("create producer failed\n");                        exit(1);                }        } while(1)        {                sleep(10);        }        return 0;}

2）、动态分配互斥量：

#include <stdlib.h>#include <pthread.h>struct foo {int             f_count;pthread_mutex_t f_lock;/* ... more stuff here ... */};struct foo * foo_alloc(void) /* allocate the object */{struct foo *fp;if ((fp = malloc(sizeof(struct foo))) != NULL) {fp->f_count = 1;if (pthread_mutex_init(&fp->f_lock, NULL) != 0) {free(fp);return(NULL);}/* ... continue initialization ... */}return(fp);}void  foo_hold(struct foo *fp) /* add a reference to the object */{pthread_mutex_lock(&fp->f_lock);fp->f_count++;pthread_mutex_unlock(&fp->f_lock);}void  foo_rele(struct foo *fp) /* release a reference to the object */{pthread_mutex_lock(&fp->f_lock);if (--fp->f_count == 0) { /* last reference */pthread_mutex_unlock(&fp->f_lock);pthread_mutex_destroy(&fp->f_lock);