#include <stdio.h>#include <stdlib.h>#include <string.h>#include <pthread.h>int ticket_cnt = 20;     /* 共有20张票 */typedef struct tag{    int s_id;    pthread_mutex_t *s_p;}DATA,*pDATA;void* handler(void *arg ){    int id = ((pDATA)arg)->s_id;    pthread_mutex_t *p_mutex = ((pDATA)arg)-> s_p;    printf("a window on !: %d \n", id);    while(1)    {        pthread_mutex_lock(p_mutex);        if(ticket_cnt == 0)        {            printf("ticket out! \n");            pthread_mutex_unlock(p_mutex);            free((pDATA)arg);            return (void*)0;        }        --ticket_cnt;        sleep(rand()%3 + 1);        printf("window: %d : a ticket sold. left : %d \n", id,ticket_cnt );        pthread_mutex_unlock(p_mutex);        sleep(rand() % 3 + 1); /* 如果不sleep，锁会一直被这个执行完的线程所占据 */    }}int main(int argc, char *argv[]){    srand(getpid());    pthread_mutex_t mutex;    pthread_mutex_init(&mutex, NULL);    int thd_cnt = atoi(argv[1]); /* 从命令行输入卖票窗口数 */    pthread_t *tds = (pthread_t*)calloc(thd_cnt,sizeof(pthread_t));    int index;    for(index = 0; index < thd_cnt; index++ )    {        pDATA p = (pDATA)calloc(1,sizeof(DATA));        p->s_id = index;        p->s_p = &mutex;        pthread_create(tds + index , NULL,handler,(void*)p);    }    printf("joining...\n");    for(index = 0; index < thd_cnt; index++)    {        pthread_join(tds[index],NULL);    }    pthread_mutex_destroy(&mutex);    return 0;}

linux多线程互斥-售票