SEMCTL(2)

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SEMCTL(2)

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semctl - ��

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        #include <sys/types.h>
        #include <sys/ipc.h>
        #include <sys/sem.h>
        
        int semctl (semid, semnum, cmd, arg)
        int semid, cmd;
        int semnum;
        union semun {
          int val;
          struct semid_ds *buf;
          ushort *array;
        } arg;

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�� semctl �� . �� semid � semnum. �� cmd, �� :

GETVAL: �� semval [��. intro(2)]. {�� .}
SETVAL: �� semval �� arg.val. {�� .} �� semadj, �� , �� 0.
GETPID: �� sempid. {�� .}
GETNCNT: �� semncnt. {�� .}
GETZCNT: �� semzcnt. {�� .}

�� cmd �� :

GETALL: �� , �� arg.array. {�� .}
SETALL: �� , �� arg.array. {�� .} �� semadj, �� , �� 0.

�� :

IPC_STAT

�� , �� semid, � ��, �� arg.buf. �� intro(2). {�� .}

IPC_SET

�� , �� semid, �� , �� , �� arg.buf:

   sem_perm.uid
   sem_perm.gid
   sem_perm.mode  /* ������ ������� 9 ��� */

�� , �� , �� , �� sem_perm.cuid �� sem_perm.uid � �� , �� semid.

IPC_RMID

�� , �� semid, �� . �� , �� , �� , �� sem_perm.cuid �� sem_perm.uid � �� , �� semid.

�� semctl �� , �� :

[EINVAL]: �� semid �� .
[EINVAL]: �� semnum �� 0 �� sem_nsems.
[EINVAL]: �� cmd, �� .
[EACCES]: �� .
[ERANGE]: �� cmd �� SETVAL �� SETALL � ��, �� , �� .
[EPERM]: �� cmd �� IPC_RMID �� IPC_SET � �� , �� sem_perm.cuid �� sem_perm.uid � �� , �� semid.
[EFAULT]: �� arg.buf �� .

��. ��
intro(2), semget(2), semop(2).

��
�� , � �� cmd:

GETVAL �� semval.

GETPID �� sempid.

GETNCNT �� semncnt.

GETZCNT �� semzcnt.

�� 0.

GETVAL	�� semval.
GETPID	�� sempid.
GETNCNT	�� semncnt.
GETZCNT	�� semzcnt.