forked from Imagelibrary/rtems
46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
/* Shm_Envelope_control *Shm_Locked_queue_Get( lq_cb )
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*
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* This routine returns an envelope control block from a shared
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* memory queue.
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*
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* Input parameters:
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* lq_cb - pointer to a locked queue control block
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*
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* Output parameters:
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* returns - pointer to an envelope control block
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* - NULL if no envelopes on specified queue
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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.rtems.org/license/LICENSE.
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*/
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#include <rtems.h>
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#include <shm_driver.h>
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Shm_Envelope_control *Shm_Locked_queue_Get(
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Shm_Locked_queue_Control *lq_cb
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)
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{
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Shm_Envelope_control *tmp_ecb;
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uint32_t tmpfront;
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tmp_ecb = NULL;
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Shm_Lock( lq_cb );
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tmpfront = Shm_Convert(lq_cb->front);
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if ( tmpfront != Shm_Locked_queue_End_of_list ) {
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tmp_ecb = &Shm_Envelopes[ tmpfront ];
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lq_cb->front = tmp_ecb->next;
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if ( tmp_ecb->next == Shm_Locked_queue_End_of_list )
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lq_cb->rear = Shm_Locked_queue_End_of_list;
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tmp_ecb->next = Shm_Locked_queue_Not_on_list;
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}
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Shm_Unlock( lq_cb );
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return( tmp_ecb );
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}
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