/* in /cs/cs3013/public/example/prodcons.c */
#include <stdio.h>
int produced, consumed; /* semaphores */
int *pn;
main()
{
    int produce(), consume();
    char *shmcreate();

    pn = (int *)shmcreate(sizeof(int));
    *pn = 0;
    consumed = screate(0);
    produced = screate(1);
    CreateProcess(produce);
    consume();
    sdelete(consumed);
    sdelete(produced);
    shmdelete(pn);
}	
produce()
{
    int i;
    for (i=0; i<5; i++) {
        swait(consumed);
        (*pn)++;  /* increment n by 1 */
        ssignal(produced);
    }
}       
consume()
{
    int i;
    for (i=0; i<5; i++) {
        swait(produced);
        printf("n is %d\n", *pn); /* print value of n */
        ssignal(consumed);
    }
}

CreateProcess(int (*pFunc)())
{
    int pid;

    if ((pid = fork()) == 0) {
        (*pFunc)();
        exit(0);
    }
    return(pid);
}