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