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| #include<pthread.h>
#include<stdio.h>
#include<stdlib.h>
#define NUM_OF_TASKS 3
#define MAX_TASK_QUEUE 11
char tasklist[MAX_TASK_QUEUE]="ABCDEFGHIJ";
int head = 0;
int tail = 0;
int quit = 0;
pthread_mutex_t g_task_lock;
pthread_cond_t g_task_cv;
void *coder(void *notused){
pthread_t tid = pthread_self();
while(!quit){
pthread_mutex_lock(&g_task_lock);
while(tail == head){
if(quit){
pthread_mutex_unlock(&g_task_lock);
pthread_exit((void *)0);
}
printf("no task now! thread %u is waiting! \n", (unsigned int)tid);
pthread_cond_wait(&g_task_cv, &g_task_lock);
printf("have task now! thread %u is grabing thw task !\n", (unsigned int)tid);
}
char task = tasklist[head++];
pthread_mutex_unlock(&g_task_lock);
printf("thread %u has a task %c now! \n", (unsigned int)tid, task);
sleep(5);
printf("thread %u finish the task %c ! \n", (unsigned int)tid, task);
}
pthread_exit((void *)0);
}
int main(int argc, char *argv[]){
pthread_t threads[NUM_OF_TASKS];
int rc;
int t;
pthread_mutex_init(&g_task_lock,NULL);
pthread_cond_init(&g_task_cv,NULL);
for(t =0 ; t < NUM_OF_TASKS; t++){
rc = pthread_create(&threads[t], NULL, coder, NULL);
if(rc){
printf("ERROR , return from pthread_create %d \n" , rc);
exit(-1);
}
}
sleep(10);
for (t =1 ; t <= 4 ; t++){
pthread_mutex_lock(&g_task_lock);
tail += t;
printf("I am Boss , I assigned %d tasks, I notify all coder! \n", t);
pthread_cond_broadcast(&g_task_cv);
pthread_mutex_unlock(&g_task_lock);
sleep(20);
}
while(head != tail ){
}
pthread_mutex_lock(&g_task_lock);
quit = 1;
pthread_cond_broadcast(&g_task_cv);
pthread_mutex_unlock(&g_task_lock);
pthread_mutex_destroy(&g_task_lock);
pthread_cond_destroy(&g_task_cv);
pthread_exit(NULL);
}
|
