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OpenSolaris 2009.06 - man page for semget (opensolaris section 2)

semget(2)				   System Calls 				semget(2)

NAME
       semget - get set of semaphores

SYNOPSIS
       #include <sys/types.h>
       #include <sys/ipc.h>
       #include <sys/sem.h>

       int semget(key_t key, int nsems, int semflg);

DESCRIPTION
       The semget() function returns the semaphore identifier associated with key.

       A  semaphore  identifier and associated data structure and set containing nsems semaphores
       (see Intro(2)) are created for key if one of the following is true:

	   o	  key is equal to IPC_PRIVATE.

	   o	  key does not already have a semaphore identifier associated with it, and  (sem-
		  flg&IPC_CREAT) is true.

       On  creation,  the data structure associated with the new semaphore identifier is initial-
       ized as follows:

	   o	  sem_perm.cuid, sem_perm.uid, sem_perm.cgid, and sem_perm.gid are set	equal  to
		  the  effective  user	ID  and  effective group ID, respectively, of the calling
		  process.

	   o	  The access permission bits of sem_perm.mode are set equal to the access permis-
		  sion bits of semflg.

	   o	  sem_nsems is set equal to the value of nsems.

	   o	  sem_otime is set equal to 0 and sem_ctime is set equal to the current time.

RETURN VALUES
       Upon  successful completion, a non-negative integer representing a semaphore identifier is
       returned. Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS
       The semget() function will fail if:

       EACCES	 A semaphore identifier exists for key, but operation permission  (see	Intro(2))
		 as specified by the low-order 9 bits of semflg would not be granted.

       EEXIST	 A  semaphore  identifier  exists  for	key but both (semflg&IPC_CREAT) and (sem-
		 flg&IPC_EXCL) are both true.

       EINVAL	 The nsems argument is either less than or equal to 0 or greater than the system-
		 imposed limit. See NOTES.

		 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 0.

       ENOENT	 A semaphore identifier does not exist for key and (semflg&IPC_CREAT) is false.

       ENOSPC	 A semaphore identifier is to be created but the system-imposed limit on the max-
		 imum  number of allowed semaphores or semaphore identifiers system-wide would be
		 exceeded. See NOTES.

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO
       ipcrm(1), ipcs(1),  rctladm(1M),  Intro(2),  semctl(2),	semop(2),  setrctl(2),	ftok(3C),
       attributes(5), standards(5)

NOTES
       The  system-imposed  limit  on the value of the nsems argument is the maintained on a per-
       process basis using the process.max-sem-nsems resource control.

       The system-imposed limit on the number of semaphore identifiers is maintained  on  a  per-
       project	basis  using  the  project.max-sem-ids	resource  control.  The  zone.max-sem-ids
       resource control limis the total number of semaphore identifiers that can be allocated  by
       a zone.

       See rctladm(1M) and setrctl(2) for information about using resource controls.

SunOS 5.11				   14 Aug 2006					semget(2)


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