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- /****************************************************************************
- * nuttx/graphics/nxterm/nxterm_sem.c
- *
- * Copyright (C) 2012, 2017 Gregory Nutt. All rights reserved.
- * Author: Gregory Nutt <gnutt@nuttx.org>
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- * 3. Neither the name NuttX nor the names of its contributors may be
- * used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- ****************************************************************************/
- /****************************************************************************
- * Included Files
- ****************************************************************************/
- #include <nuttx/config.h>
- #include <unistd.h>
- #include <semaphore.h>
- #include <assert.h>
- #include <errno.h>
- #include "nxterm.h"
- #ifdef CONFIG_DEBUG_GRAPHICS
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: nxterm_semwait and nxterm_sempost
- *
- * Description:
- * If debug is on, then lower level code may attempt console output while
- * we are doing console output! In this case, we will toss the nested
- * output to avoid deadlocks and infinite loops.
- *
- * Input Parameters:
- * priv - Driver data structure
- *
- * Returned Value:
- *
- *
- ****************************************************************************/
- int nxterm_semwait(FAR struct nxterm_state_s *priv)
- {
- pid_t me;
- int ret;
- /* Does I already hold the semaphore */
- me = getpid();
- if (priv->holder != me)
- {
- /* No.. then wait until the thread that does hold it is finished with it */
- ret = nxsem_wait(&priv->exclsem);
- if (ret == OK)
- {
- /* No I hold the semaphore */
- priv->holder = me;
- }
- return ret;
- }
- /* Abort, abort, abort! I have been re-entered */
- return -EBUSY;
- }
- int nxterm_sempost(FAR struct nxterm_state_s *priv)
- {
- /* Make sure that I really hold the semaphore */
- DEBUGASSERT(priv->holder == getpid());
- /* Then let go of it */
- priv->holder = NO_HOLDER;
- return nxsem_post(&priv->exclsem);
- }
- #endif /* CONFIG_DEBUG_GRAPHICS */
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