#include<stdio.h>

 #include<pthread.h>

 #define MAX 20

 pthread_mutex_t the_mutex;

 pthread_cond_t condc, condp;

 int buffer = ;

 void *producer(void *ptr)

 {

     int i;

     for(i = ; i <= MAX; i++)

     {

         pthread_mutex_lock(&the_mutex);

         while(buffer != ) pthread_cond_wait(&condp, &the_mutex);

         buffer = i;

         printf("%d ", buffer);

         pthread_cond_signal(&condc);

         pthread_mutex_unlock(&the_mutex);

     }

     pthread_exit();

 }

 void *consumer(void *ptr)

 {

     int i;

     for(i = ; i < MAX; i++)

     {

         pthread_mutex_lock(&the_mutex);

         while(buffer == )pthread_cond_wait(&condc, &the_mutex);

         buffer = ;

         printf("%d ", buffer);

         pthread_cond_signal(&condp);

         pthread_mutex_unlock(&the_mutex);

     }

     pthread_exit();

 }

 int main(void)

 {

     pthread_t pro, con;

     pthread_mutex_init(&the_mutex, );

     pthread_cond_init(&condc, );

     pthread_cond_init(&condp, );

     pthread_create(&con, , consumer, );

     pthread_create(&pro, , producer, );

     pthread_join(pro, );

     pthread_join(con, );

     pthread_cond_destroy(&condc);

     pthread_cond_destroy(&condp);

     pthread_mutex_destroy(&the_mutex);

 }

gcc -lpthread -o procro procro.c