// pe.c
// 哲学家吃空心粉的问题
// Copyright 2011 shiweifu <shiweifu@126.com>
//
#define _REENTRANT
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include
<semaphore.h>
#include <pthread.h>#define STR_MAX 256typedef
struct philosophy {
char name[STR_MAX];
sem_t *left;
sem_t *right;
char is_stop;
} philosophy;void *thread_function(void *arg);int main(int argc, char **argv) {
int i = 0;
//五只悲剧的筷子
sem_t sems[5];
//五个NC哲学家
philosophy philers[5];
pthread_t threads[5];
int res = 0;
char tmp[255] = {0};
for(; i < 5; i++) {
philers[i].left = &sems[i];
philers[i].right = &sems[i];
if (i == 4) {
philers[i].left = &sems[0];
}
philers[i].is_stop = 0;
sprintf(tmp,"NC %d",i);
strncpy(philers[i].name,tmp,255);
}
for(i = 0; i < 5; i++) {
sem_init(&sems[i], 0, 10); res
= pthread_create(&threads[i],NULL,thread_function,&philers[i]);
if (res != 0) {
perror("创建线程出错啦...");
}
}
//给这群吃货吃20秒
sleep(20);
for(i = 0; i < 5; i++) {
philers[i].is_stop = 1;
pthread_join(threads[i],NULL);
}
for(i = 0; i < 5; i++) {
sem_destroy(&sems[i]);
} exit(EXIT_SUCCESS);
}
void *thread_function(void *arg) {
philosophy *p = arg;
while (1) {
if (sem_trywait(p->left) == 0) {
if (sem_trywait(p->right) == 0) {
printf("红烧翅膀真好吃,我是%s\n",p->name);
sem_post(p->left);
sem_post(p->right);
sleep(1); }
else {
sem_post(p->left);
}
}
if (p->is_stop == 1) {
break;
}
}
pthread_exit(NULL);
}
