C++ (Cpp) get_shared_mem Examples

Example #1

File: father.c Project: BackupTheBerlios/unisimu-svn

void father(void) {
    int* apple_sp_ptr;
    int apple_sp;

    char* plate;

    HERE

    P(SEM_CAN_PUT);
    P(SEM_APPLE_SP);

    HERE

    apple_sp_ptr = (int*) get_shared_mem(SHM_APPLE_SP, SHM_APPLE_SP_SZ);
    if (apple_sp_ptr == NULL) err("Can't get 'apple_sp'.");
    apple_sp = *apple_sp_ptr;

    fprintf(stderr, "apple_sp = %d\n", apple_sp);

    HERE

    plate = (char*) get_shared_mem(SHM_PLATE, SHM_PLATE_SZ);
    if (plate == NULL) err("Can't get 'plate'.");

    HERE

    printf("Father is putting an apple...\n");
    fflush(stdout);

    HERE

    strcpy(plate + apple_sp * BUFSIZE, "apple");
    apple_sp++;

    HERE

    *apple_sp_ptr = apple_sp;
    commit_shared_ptr(apple_sp_ptr);

    HERE

    commit_shared_ptr(plate);

    HERE

    V(SEM_APPLE_SP);
    V(SEM_CAN_GET_APPLE);
}

Example #2

File: time-sem.c Project: kheradmand/Break

void main (int argc, char **argv)
{
    int num_iter;
    int num_child;
    int i;
    struct timeval first;
    struct timeval last;
    long ms;
    int pid;
    unsigned long *shared_counter;

    if (argc != 3) {
	fprintf (stderr, "Usage: time-sem num-child num iter\n");
	exit (1);
    }

    num_child = atoi (argv[1]);
    num_iter = atoi (argv[2]);

    /* allocate shared memory for the shared_counter */
    shared_counter = get_shared_mem(sizeof(*shared_counter));

    /* initialize counter to 0 */
    *shared_counter = 0;

    accept_mutex_init ();

    /* parent grabs mutex until done spawning children */
    accept_mutex_on ();

    for (i = 0; i < num_child; ++i) {
	pid = fork();
	if (pid == 0) {
	    /* child, do our thing */
	    accept_mutex_child_init();
	    for (i = 0; i < num_iter; ++i) {
		unsigned long tmp;

		accept_mutex_on ();
		tmp = *shared_counter;
		YIELD;
		*shared_counter = tmp + 1;
		accept_mutex_off ();
	    }
	    exit (0);
	} else if (pid == -1) {
	    perror ("fork");
	    exit (1);
	}
    }

    /* a quick test to see that nothing is screwed up */
    if (*shared_counter != 0) {
	puts ("WTF! shared_counter != 0 before the children have been started!");
	exit (1);
    }

    gettimeofday (&first, NULL);
    /* launch children into action */
    accept_mutex_off ();
    for (i = 0; i < num_child; ++i) {
	if (wait(NULL) == -1) {
	    perror ("wait");
	}
    }
    gettimeofday (&last, NULL);

    if (*shared_counter != num_child * num_iter) {
	printf ("WTF! shared_counter != num_child * num_iter!\n"
		"shared_counter = %lu\nnum_child = %d\nnum_iter=%d\n",
		*shared_counter,
		num_child, num_iter);
    }

    last.tv_sec -= first.tv_sec;
    ms = last.tv_usec - first.tv_usec;
    if (ms < 0) {
	--last.tv_sec;
	ms += 1000000;
    }
    last.tv_usec = ms;
    printf ("%8lu.%06lu\n", last.tv_sec, last.tv_usec);

    accept_mutex_cleanup();

    exit(0);
}