1 /**************************************************************************/
2 /* */
3 /* Copyright (c) Microsoft Corporation. All rights reserved. */
4 /* */
5 /* This software is licensed under the Microsoft Software License */
6 /* Terms for Microsoft Azure RTOS. Full text of the license can be */
7 /* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
8 /* and in the root directory of this software. */
9 /* */
10 /**************************************************************************/
11
12
13 /**************************************************************************/
14 /**************************************************************************/
15 /** */
16 /** POSIX wrapper for THREADX */
17 /** */
18 /** */
19 /** */
20 /**************************************************************************/
21 /**************************************************************************/
22
23 /* Include necessary system files. */
24
25 #include "tx_api.h" /* Threadx API */
26 #include "pthread.h" /* Posix API */
27 #include "tx_posix.h" /* Posix API */
28 #include "px_int.h" /* Posix helper functions */
29
30
31
32 /**************************************************************************/
33 /* */
34 /* FUNCTION RELEASE */
35 /* */
36 /* sched_yield PORTABLE C */
37 /* 6.1.7 */
38 /* AUTHOR */
39 /* */
40 /* William E. Lamie, Microsoft Corporation */
41 /* */
42 /* DESCRIPTION */
43 /* */
44 /* This routine forces the running thread to relinquish the CPU */
45 /* */
46 /* INPUT */
47 /* */
48 /* void . */
49 /* */
50 /* OUTPUT */
51 /* */
52 /* OK If successful */
53 /* ERROR IF fails */
54 /* */
55 /* CALLS */
56 /* */
57 /* posix_in_thread_context Checks thread is called from its context.*/
58 /* tx_thread_relinquish Relinquishes processor control */
59 /* posix_internal_error Returns generic error */
60 /* */
61 /* CALLED BY */
62 /* */
63 /* Application Code */
64 /* */
65 /* RELEASE HISTORY */
66 /* */
67 /* DATE NAME DESCRIPTION */
68 /* */
69 /* 06-02-2021 William E. Lamie Initial Version 6.1.7 */
70 /* */
71 /**************************************************************************/
sched_yield(VOID)72 INT sched_yield(VOID)
73 {
74
75 /* Make sure we're calling this routine from a thread context. */
76 if (!posix_in_thread_context())
77 {
78 /* return POSIX error. */
79 posix_internal_error(444);
80
81 /* return error. */
82 return (ERROR);
83 }
84
85 /* This relinquishes the CPU. */
86 tx_thread_relinquish();
87 return(OK);
88 }
89
