utility/rtos_compatibility_layers/posix/px_pth_yield.c


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76

/***************************************************************************
 * Copyright (c) 2024 Microsoft Corporation
 * Copyright (c) 2026-present Eclipse ThreadX contributors
 *
 * This program and the accompanying materials are made available under the
 * terms of the MIT License which is available at
 * https://opensource.org/licenses/MIT.
 *
 * SPDX-License-Identifier: MIT
 **************************************************************************/


/**************************************************************************/
/**************************************************************************/
/**                                                                       */
/** POSIX wrapper for THREADX                                             */
/**                                                                       */
/**                                                                       */
/**                                                                       */
/**************************************************************************/
/**************************************************************************/

/* Include necessary system files.  */

#include "tx_api.h"    /* Threadx API */
#include "pthread.h"  /* Posix API */
#include "px_int.h"    /* Posix helper functions */


/**************************************************************************/
/*                                                                        */
/*  FUNCTION                                               RELEASE        */
/*                                                                        */
/*    pthread_yield                                       PORTABLE C      */
/*                                                           6.1.7        */
/*  AUTHOR                                                                */
/*                                                                        */
/*    William E. Lamie, Microsoft Corporation                             */
/*                                                                        */
/*  DESCRIPTION                                                           */
/*                                                                        */
/*    This subroutine forces the calling thread to relinquish use of its  */
/*    processor,and to wait in the run queue before it is scheduled again.*/
/*    If the run queue is empty when this subroutine is called, the       */
/*    calling thread is immediately rescheduled.                          */
/*                                                                        */
/*  INPUT                                                                 */
/*                                                                        */
/*     Nothing                                                            */
/*                                                                        */
/*  OUTPUT                                                                */
/*                                                                        */
/*     None                                                               */
/*                                                                        */
/*  CALLS                                                                 */
/*                                                                        */
/*    posix_internal_error                 posix internal error function  */
/*    tx_thread_relinquish                 ThreadX function               */
/*                                                                        */
/*  CALLED BY                                                             */
/*                                                                        */
/*    Application Code                                                    */
/*                                                                        */
/**************************************************************************/
VOID pthread_yield(VOID)
{
     /* Make sure we're calling this routine from a thread context.  */
    if (!posix_in_thread_context())
    {
        /* return POSIX error.  */
        posix_internal_error(444);
    }

    /* This relinquishes the CPU.  */
    tx_thread_relinquish();
}