semget man page on HP-UX

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semget(2)							     semget(2)

NAME
       semget - get set of semaphores

SYNOPSIS
DESCRIPTION
       returns the semaphore identifier associated with key.

       A semaphore identifier and associated data structure and set containing
       nsems semaphores are created for key if one of the following is true:

	      key is equal to This call creates a new identifier,  subject  to
	      available	 resources.   The  identifier  is  never  returned  by
	      another call to until it has been released  by  a	 call  to  The
	      identifier  should  be  used  among  the calling process and its
	      descendents; however, it is not a requirement.  The resource can
	      be accessed by any process having the proper permissions.

	      key does not already have a semaphore identifier associated with
	      it, and (semflg & is "true".

       Specific behavior can be requested by ORing the	following  masks  into
       semflg.

	      Create  a semaphore identifier if one does not already exist for
	      key.

	      If is specified and key already has a semaphore identifier asso‐
	      ciated with it, return an error.

       The  low-order 9 bits of semflg are the semaphore operation permissions
       which are defined in glossary(9).

       Upon creation, the data structure associated  with  the	new  semaphore
       identifier is initialized as follows:

	      In  the operation-permission structure, and are set equal to the
	      effective-user-ID of the calling process, while and are  set  to
	      the effective-group-ID of the calling process.

	      The low-order 9 bits of are set equal to the low-order 9 bits of
	      semflg.

	      is set equal to the value of nsems.

	      is set equal to 0 and is set equal to the current time.

   Security Restrictions
       Some or all of the actions associated with this system call are subject
       to compartmental restrictions. See compartments(5) for more information
       about compartmentalization on systems that support that feature.	  Com‐
       partmental  restrictions can be overridden if the process possesses the
       privilege (PRIV_COMMALLOWED).  Processes owned by the superuser may not
       have  this privilege.  Processes owned by any user may have this privi‐
       lege, depending on system configuration.

       See privileges(5) for more information about privileged access on  sys‐
       tems that support fine-grained privileges.

EXAMPLES
       The  following call to returns a semid associated with the key returned
       by If a semid associated with the key does not exist, a new semid,  set
       of  4  semaphores, and associated data structure will be created.  If a
       semid for the key already exists, the semid is simply returned.

RETURN VALUE
       Upon successful completion, a non-negative integer, namely a  semaphore
       identifier,  is	returned.  Otherwise, a value of −1 is returned and is
       set to indicate the error.

ERRORS
       fails if one or more of the following is true:

	      nsems	     is either less than or equal to zero  or  greater
			     than the system-imposed limit.

	      A semaphore identifier exists for
			     key, but operation permission as specified by the
			     low-order 9 bits of semflg would not be granted.

	      A semaphore identifier exists for
			     key, but the number  of  semaphores  in  the  set
			     associated	 with it is less than nsems, and nsems
			     is not equal to zero.

	      A semaphore identifier does not exist for
			     key and (semflg & is "false".

	      A semaphore identifier is to be created,
			     but the system-imposed limit on the maximum  num‐
			     ber  of allowed semaphore identifiers system wide
			     would be exceeded.

	      A semaphore identifier exists for
			     key but is "true".

SEE ALSO
       ipcrm(1), ipcs(1), semctl(2), semop(2), stdipc(3C).

STANDARDS CONFORMANCE
								     semget(2)
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