87 lines
3.0 KiB
C
87 lines
3.0 KiB
C
/****************************************************************************
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* libs/libnx/nxtk/nxtk_synch.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <nuttx/nx/nx.h>
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#include <nuttx/nx/nxtk.h>
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#include <nuttx/nx/nxmu.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxtk_synch
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*
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* Description:
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* This interface can be used to synchronize the window client with the
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* NX server. It really just implements an 'echo': A synch message is
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* sent from the window client to the server which then responds
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* immediately by sending the NXEVENT_SYNCHED back to the windows client.
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*
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* Due to the highly asynchronous nature of client-server communications,
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* nxtk_synch() is sometimes necessary to assure that the client and server
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* are fully synchronized in time.
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*
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* Usage by the window client might be something like this:
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*
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* extern bool g_synched;
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* extern sem_t g_synch_sem;
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*
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* g_synched = false;
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* ret = nxtk_synch(hwnd, handle);
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* if (ret < 0)
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* {
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* -- Handle the error --
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* }
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*
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* while (!g_synched)
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* {
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* ret = sem_wait(&g_sync_sem);
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* if (ret < 0)
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* {
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* -- Handle the error --
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* }
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* }
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*
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* When the window listener thread receives the NXEVENT_SYNCHED event, it
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* would set g_synched to true and post g_synch_sem, waking up the above
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* loop.
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*
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* Input Parameters:
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* hfwnd - The window to be synched
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* arg - An argument that will accompany the block messages (This is arg2
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* in the event callback).
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*
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* Returned Value:
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* OK on success; ERROR on failure with errno set appropriately
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*
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****************************************************************************/
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int nxtk_synch(NXTKWINDOW hfwnd, FAR void *arg)
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{
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return nx_synch((NXWINDOW)hfwnd, arg);
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}
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