42 lines
850 B
C
42 lines
850 B
C
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <sys/types.h>
|
||
|
|
#include <sys/wait.h>
|
||
|
|
#include <sys/ipc.h>
|
||
|
|
#include <sys/shm.h>
|
||
|
|
#include <sys/stat.h>
|
||
|
|
#include <sys/sem.h>
|
||
|
|
|
||
|
|
int main()
|
||
|
|
{
|
||
|
|
unsigned long max = 1UL;
|
||
|
|
|
||
|
|
int semId;
|
||
|
|
|
||
|
|
semId = semget(IPC_PRIVATE, 1, 00600);
|
||
|
|
semctl(semId, 0, SETVAL, 1);
|
||
|
|
struct sembuf unlock = {0, 1, SEM_UNDO};
|
||
|
|
|
||
|
|
for (max = 1UL; max < 33366475776UL; max++)
|
||
|
|
{
|
||
|
|
// Incrementing semaphore.
|
||
|
|
if (semop(semId, &unlock, 1) < 0)
|
||
|
|
{
|
||
|
|
printf("Max semaphore value: %lu\n", max);
|
||
|
|
|
||
|
|
// Flagging semaphore for deletion.
|
||
|
|
if (semctl(semId, 0, IPC_RMID) < 0)
|
||
|
|
{
|
||
|
|
perror("can't deallocate\n");
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
semctl(semId, 0, IPC_RMID);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|