incubator-nuttx/sched/task/task_getpid.c

105 lines
3.3 KiB
C

/****************************************************************************
* sched/task/task_getpid.c
*
* SPDX-License-Identifier: Apache-2.0
*
* 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 <sys/types.h>
#include <unistd.h>
#include <sched.h>
#include <errno.h>
#include "sched/sched.h"
#include "task/task.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxsched_getpid
*
* Description:
* Get the Process ID of the currently executing task.
*
* Input parameters:
* None
*
* Returned Value:
* Normally when called from user applications, nxsched_getpid() will
* return the Process ID of the currently executing task. that is,
* the main task for the task groups. There is no specification for
* any errors returned from nxsched_getpid().
*
****************************************************************************/
pid_t nxsched_getpid(void)
{
FAR struct tcb_s *rtcb;
/* Get the TCB at the head of the ready-to-run task list. That
* will usually be the currently executing task. There is are two
* exceptions to this:
*
* Early in the start-up sequence, the ready-to-run list may be
* empty! In this case, of course, the CPU0 start-up/IDLE thread with
* pid == 0 must be running, and
*/
rtcb = this_task();
if (rtcb != NULL)
{
/* Yes.. Return the Process ID */
return rtcb->group->tg_pid;
}
/* We must have been called earlier in the start up sequence from the
* start-up/IDLE thread before the ready-to-run list has been initialized.
*/
return IDLE_PROCESS_ID;
}
/****************************************************************************
* Name: getpid
*
* Description:
* Get the Process ID of the currently executing task.
*
* Input parameters:
* None
*
* Returned Value:
* Normally when called from user applications, getpid() will return the
* Process ID of the currently executing task. that is, the main task
* for the task groups. There is no specification for any errors
* returned from getpid().
*
****************************************************************************/
pid_t getpid(void)
{
return nxsched_getpid();
}