nuttx/libs/libnx/nxtk/nxtk_synch.c
Alin Jerpelea 88fa869a04 libnx: Author Gregory Nutt: update licenses to Apache
Gregory Nutt has submitted the SGA and we can migrate the licenses
 to Apache.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2021-02-25 01:44:30 -08:00

87 lines
3.0 KiB
C

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