source: liacs/os/assignment4/assignment4c.c@ 201

#include <sysexits.h>
#include <stdlib.h>
#include <pthread.h>
#include <stdio.h>
#include <unistd.h>


static int x = 0;
static int y = 0;

static int flagA = 0;
static int flagB = 0;
static int turn = 0;


//Consumer
void *procA() {
    for ( ;; ) {
        //hungry, ask cheff to prepare something
        flagA = 1;
        turn = 1;
        while ( flagB && turn == 1 ) { usleep(1); }
        //eat
        printf("Turn A\n");
        y = 0;
        flagA = 0;



    }
    pthread_exit(NULL);
}

//Producer
void *procB() {
    for ( ;; ) {
        //prepare food, and allow eating
        flagB = 1;
        turn = 0;
        while ( flagA && turn == 0 ) { usleep(1); }
        printf("Turn B\n");
        y = 1;
        flagB = 0;
    }
    pthread_exit(NULL);
}


int main (int argc, char * argv[]) {

    //create 2 threads
    pthread_t thread0, thread1;
    pthread_create(&thread0, NULL, procA, NULL);
    pthread_create(&thread1, NULL, procB, NULL);

    //debugging
    for ( ;; ) {
        printf("flagA:%i flagB:%i turn:%i, y:%i\n", flagA, flagB, turn, y);
        sleep(1);
    }
    pthread_exit(NULL);
    return(EX_OK);
}