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class_open(3)
NAME
  class_open - Initialize the class scheduler database.

SYNOPSIS
  #include <apar_types.h>
  #include <sys/class.h>

  class_open(
	  apart_id,
	  part_id,
	  *class_apar_handle_t,
	  handle );

PARAMETERS
  part_id
      Input which describes the unique partition identifier.

  handle
      Output that displays the descriptor used in calls to reference the
      partition.

DESCRIPTION
  The class_open function is used to prepare the class scheduler database for
  use as follows:

    ·  Opening the disk file (if any).

    ·  Creating (or attaching to) a shared memory section.

    ·  Creating (or attaching to) a semaphore.

    ·  Initializing the database if one did not aready exist.

  Before class scheduling can be used for a partition, its class scheduler
  database must be initialized.	  At the first call of class_open() since the
  system last started, the function creates a shared memory segment for the
  partition database and, if it exists on disk, reads it into the shared
  memory.  A semaphore is also created that is used to synchronize potential
  simultaneous database updates (from class_admin and runclass, for
  instance).  If no database exists for the partition one will be created
  with the default configuration

  On subsequent calls to class_open() the function attaches to the existing
  shared memory and semaphore.






RESTRICTIONS
  The caller must have root access rights.



RETURN VALUES
  CLASS_SUCCESS
      Operation successfully completed.

  CLASS_DEFAULT_CONFIGURED
      The class_open succeeded but no database existed.	 A new database was
      created with default configuration settings.

  CLASS_NOT_SUSER
      The calling process is not super user (root) and permission is denied.

  CLASS_MEM_ALLOC_FAILURE
      The malloc function failed to get memory for handle.

  CLASS_FILE_FAILURE.
      Failed to access disk file, if it exists.

  CLASS_SHARED_MEM_FAILURE
      Failed to create or attach to shared memory.

  CLASS_SEMAPHORE_FAILURE
      Failed to create or attach to semaphore.

SEE ALSO
  class_scheduling(4), runclass(1), class_admin(8)

Index for Section 3

Alphabetical listing for C

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