int main(void)
{
pthread_t ptid;
mylock_init(&lock);
pthread_create(&ptid, NULL, pthread_fun, NULL);
add(19);
pthread_join(ptid, NULL);
print("main");
return 0;
}
int main()
{
pid_t pid;
int count;
int *shm_p;
int shm_id, proj_id;
key_t shm_key;
lockid = mylock_init();
if (lockid == -1) {
exit(1);
}
proj_id = 1234;
// use PATHNAME and proj_id to generate shm_key
if ((shm_key = ftok(PATHNAME, proj_id)) == -1) {
perror("ftok()");
exit(1);
}
/* create a shared memory with shm_key and
set shared memory access permission 0666
*/
shm_id = shmget(shm_key, sizeof(int), IPC_CREAT|IPC_EXCL|0600);
if (shm_id < 0) {
perror("shmget()");
exit(1);
}
// attach shared memory to parent process
shm_p = (int *)shmat(shm_id, NULL, 0);
if ((void *)shm_p == (void *)-1) {
perror("shmat()");
exit(1);
}
*shm_p = 0;
for (count = 0; count < COUNT; count++) {
pid = fork();
if (pid < 0) {
perror("fork()");
exit(1);
}
if (pid == 0) {
do_child(proj_id);
}
}
for (count = 0; count < COUNT; count++) {
wait(NULL);
}
printf("shm_p: %d\n", *shm_p);
// detach shared memory from parent process
if (shmdt(shm_p) < 0) {
perror("shmdt()");
exit(1);
}
// delete shared memory
if (shmctl(shm_id, IPC_RMID, NULL) < 0) {
perror("shmctl()");
exit(1);
}
mylock_destroy(lockid);
exit(0);
}
