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/*
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* Semaphore Manager
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*
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* DESCRIPTION:
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*
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* This package is the implementation of the Semaphore Manager.
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* This manager utilizes standard Dijkstra counting semaphores to provide
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* synchronization and mutual exclusion capabilities.
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*
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* Directives provided are:
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*
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* + create a semaphore
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* + get an ID of a semaphore
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* + delete a semaphore
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* + acquire a semaphore
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* + release a semaphore
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*
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* COPYRIGHT (c) 1989-1999.
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* On-Line Applications Research Corporation (OAR).
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*
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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* http://www.OARcorp.com/rtems/license.html.
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*
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* $Id: semcreate.c,v 1.2 2001-09-27 11:59:19 chris Exp $
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*/
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#include <rtems/system.h>
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#include <rtems/rtems/status.h>
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#include <rtems/rtems/support.h>
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#include <rtems/rtems/attr.h>
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#include <rtems/score/isr.h>
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#include <rtems/score/object.h>
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#include <rtems/rtems/options.h>
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#include <rtems/rtems/sem.h>
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#include <rtems/score/coremutex.h>
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#include <rtems/score/coresem.h>
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#include <rtems/score/states.h>
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#include <rtems/score/thread.h>
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#include <rtems/score/threadq.h>
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#if defined(RTEMS_MULTIPROCESSING)
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#include <rtems/score/mpci.h>
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#endif
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#include <rtems/score/sysstate.h>
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#include <rtems/score/interr.h>
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/*PAGE
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*
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* rtems_semaphore_create
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*
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* This directive creates a semaphore and sets the initial value based
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* on the given count. A semaphore id is returned.
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*
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* Input parameters:
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* name - user defined semaphore name
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* count - initial count of semaphore
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* attribute_set - semaphore attributes
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* priority_ceiling - semaphore's ceiling priority
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* id - pointer to semaphore id
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*
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* Output parameters:
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* id - semaphore id
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* RTEMS_SUCCESSFUL - if successful
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* error code - if unsuccessful
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*/
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rtems_status_code rtems_semaphore_create(
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rtems_name name,
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unsigned32 count,
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rtems_attribute attribute_set,
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rtems_task_priority priority_ceiling,
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Objects_Id *id
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)
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{
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register Semaphore_Control *the_semaphore;
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CORE_mutex_Attributes the_mutex_attributes;
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CORE_semaphore_Attributes the_semaphore_attributes;
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unsigned32 lock;
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if ( !rtems_is_name_valid( name ) )
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return RTEMS_INVALID_NAME;
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#if defined(RTEMS_MULTIPROCESSING)
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if ( _Attributes_Is_global( attribute_set ) ) {
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if ( !_System_state_Is_multiprocessing )
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return RTEMS_MP_NOT_CONFIGURED;
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if ( _Attributes_Is_inherit_priority( attribute_set ) )
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return RTEMS_NOT_DEFINED;
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} else
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#endif
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if ( _Attributes_Is_inherit_priority( attribute_set ) ||
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_Attributes_Is_priority_ceiling( attribute_set ) ) {
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if ( ! ( (_Attributes_Is_binary_semaphore( attribute_set ) ||
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_Attributes_Is_simple_binary_semaphore( attribute_set )) &&
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_Attributes_Is_priority( attribute_set ) ) )
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return RTEMS_NOT_DEFINED;
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}
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if ( !_Attributes_Is_counting_semaphore( attribute_set ) && ( count > 1 ) )
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return RTEMS_INVALID_NUMBER;
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_Thread_Disable_dispatch(); /* prevents deletion */
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the_semaphore = _Semaphore_Allocate();
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if ( !the_semaphore ) {
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_Thread_Enable_dispatch();
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return RTEMS_TOO_MANY;
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}
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#if defined(RTEMS_MULTIPROCESSING)
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if ( _Attributes_Is_global( attribute_set ) &&
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! ( _Objects_MP_Allocate_and_open( &_Semaphore_Information, name,
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the_semaphore->Object.id, FALSE ) ) ) {
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_Semaphore_Free( the_semaphore );
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_Thread_Enable_dispatch();
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return RTEMS_TOO_MANY;
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}
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#endif
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the_semaphore->attribute_set = attribute_set;
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/*
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* If it is not a counting semaphore, then it is either a
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* simple binary semaphore or a more powerful mutex style binary
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* semaphore.
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*/
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if ( !_Attributes_Is_counting_semaphore( attribute_set ) ) {
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if ( _Attributes_Is_inherit_priority( attribute_set ) )
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the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT;
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else if ( _Attributes_Is_priority_ceiling( attribute_set ) )
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the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING;
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else if ( _Attributes_Is_priority( attribute_set ) )
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the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY;
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else
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the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_FIFO;
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if ( _Attributes_Is_binary_semaphore( attribute_set ) ) {
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the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES;
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switch ( the_mutex_attributes.discipline ) {
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case CORE_MUTEX_DISCIPLINES_FIFO:
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case CORE_MUTEX_DISCIPLINES_PRIORITY:
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the_mutex_attributes.only_owner_release = FALSE;
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break;
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case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING:
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case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT:
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the_mutex_attributes.only_owner_release = TRUE;
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break;
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}
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} else {
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the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_BLOCKS;
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the_mutex_attributes.only_owner_release = FALSE;
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}
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the_mutex_attributes.priority_ceiling = priority_ceiling;
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if ( count == 1 )
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lock = CORE_MUTEX_UNLOCKED;
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else
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lock = CORE_MUTEX_LOCKED;
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_CORE_mutex_Initialize(
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&the_semaphore->Core_control.mutex,
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OBJECTS_RTEMS_SEMAPHORES,
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&the_mutex_attributes,
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lock,
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#if defined(RTEMS_MULTIPROCESSING)
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_Semaphore_MP_Send_extract_proxy
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#else
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NULL
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#endif
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);
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} else {
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if ( _Attributes_Is_priority( attribute_set ) )
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the_semaphore_attributes.discipline = CORE_SEMAPHORE_DISCIPLINES_PRIORITY;
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else
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the_semaphore_attributes.discipline = CORE_SEMAPHORE_DISCIPLINES_FIFO;
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/*
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* This effectively disables limit checking.
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*/
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the_semaphore_attributes.maximum_count = 0xFFFFFFFF;
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/*
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* The following are just to make Purify happy.
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*/
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the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES;
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the_mutex_attributes.priority_ceiling = PRIORITY_MINIMUM;
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_CORE_semaphore_Initialize(
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&the_semaphore->Core_control.semaphore,
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OBJECTS_RTEMS_SEMAPHORES,
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&the_semaphore_attributes,
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count,
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#if defined(RTEMS_MULTIPROCESSING)
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_Semaphore_MP_Send_extract_proxy
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#else
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NULL
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#endif
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);
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}
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_Objects_Open( &_Semaphore_Information, &the_semaphore->Object, &name );
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*id = the_semaphore->Object.id;
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#if defined(RTEMS_MULTIPROCESSING)
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if ( _Attributes_Is_global( attribute_set ) )
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_Semaphore_MP_Send_process_packet(
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SEMAPHORE_MP_ANNOUNCE_CREATE,
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the_semaphore->Object.id,
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name,
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);
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#endif
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_Thread_Enable_dispatch();
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return RTEMS_SUCCESSFUL;
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}
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