/************************************************************************
* sched/task/task_getpid.c
*
* Copyright (C) 2007, 2009, 2014 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 <sys/types.h>
#include <unistd.h>
#include <sched.h>
#include "sched/sched.h"
#include "task/task.h"
/************************************************************************
* Pre-processor Definitions
************************************************************************/
/************************************************************************
* Private Type Declarations
************************************************************************/
/************************************************************************
* Global Variables
************************************************************************/
/************************************************************************
* Private Variables
************************************************************************/
/************************************************************************
* Private Function Prototypes
************************************************************************/
/************************************************************************
* Public Functions
************************************************************************/
/************************************************************************
* Name: getpid
*
* Description:
* Get the task ID of the currently executing task.
*
************************************************************************/
pid_t getpid(void)
{
FAR struct tcb_s *rtcb;
/* Get the the TCB at the head of the ready-to-run task list. That
* will be the currently executing task. There is an exception to
* this: Verify early in the start-up sequence, the g_readytorun
* list may be empty! This case, of course, the start-up/IDLE thread
* with pid == 0 must be running.
*/
rtcb = (FAR struct tcb_s *)g_readytorun.head;
if (rtcb)
{
/* Return the task ID from the TCB at the head of the ready-to-run
* task list
*/
return rtcb->pid;
}
/* We must have been called earlier in the start up sequence from the
* start-up/IDLE thread before the g_readytorun list has been initialized.
*/
return 0;
}
