1 /***************************************************************************
2 * Copyright (c) 2024 Microsoft Corporation
3 *
4 * This program and the accompanying materials are made available under the
5 * terms of the MIT License which is available at
6 * https://opensource.org/licenses/MIT.
7 *
8 * SPDX-License-Identifier: MIT
9 **************************************************************************/
10
11
12 /**************************************************************************/
13 /**************************************************************************/
14 /** */
15 /** POSIX wrapper for THREADX */
16 /** */
17 /** */
18 /** */
19 /**************************************************************************/
20 /**************************************************************************/
21
22 /* Include necessary system files. */
23
24 #include "tx_api.h" /* Threadx API */
25 #include "pthread.h" /* Posix API */
26 #include "px_int.h" /* Posix helper functions */
27
28
29 /**************************************************************************/
30 /* */
31 /* FUNCTION RELEASE */
32 /* */
33 /* pthread_cond_signal PORTABLE C */
34 /* 6.1.7 */
35 /* AUTHOR */
36 /* */
37 /* William E. Lamie, Microsoft Corporation */
38 /* */
39 /* DESCRIPTION */
40 /* */
41 /* This function shall unblock at least one of the threads that are */
42 /* blocked on the specified condition variable cond */
43 /* (if any threads are blocked on cond).If more than one thread is */
44 /* blocked on a condition variable, the scheduling policy shall */
45 /* determine the order in which threads are unblocked.When each thread */
46 /* unblocked as a result of a pthread_cond_signal returns from its call*/
47 /* to pthread_cond_wait or pthread_cond_timedwait, the thread shall own*/
48 /* the mutex with which it called pthread_cond_wait or */
49 /* pthread_cond_timedwait.The thread(s) that are unblocked shall */
50 /* contend for the mutex according to the scheduling policy */
51 /* (if applicable), and as if each had called pthread_mutex_lock. */
52 /* The pthread_cond_broadcast or pthread_cond_signal functions may be */
53 /* called by a thread whether or not it currently owns the mutex that */
54 /* threads calling pthread_cond_wait or pthread_cond_timedwait have */
55 /* associated with the condition variable during their waits; however, */
56 /* if predictable scheduling behavior is required,then that mutex shall*/
57 /* be locked by the thread calling pthread_cond_signal. */
58 /* This function shall have no effect if there are no threads currently*/
59 /* blocked on cond. */
60 /* */
61 /* INPUT */
62 /* */
63 /* Nothing */
64 /* */
65 /* OUTPUT */
66 /* */
67 /* Nothing */
68 /* */
69 /* CALLS */
70 /* */
71 /* tx_semaphore_prioritize line up pthreads waiting at semaphore*/
72 /* tx_semaphore_put ThreadX semaphore put service */
73 /* */
74 /* CALLED BY */
75 /* */
76 /* Application Code */
77 /* */
78 /* RELEASE HISTORY */
79 /* */
80 /* DATE NAME DESCRIPTION */
81 /* */
82 /* 06-02-2021 William E. Lamie Initial Version 6.1.7 */
83 /* */
84 /**************************************************************************/
pthread_cond_signal(pthread_cond_t * cond)85 INT pthread_cond_signal(pthread_cond_t *cond)
86 {
87
88 TX_SEMAPHORE *semaphore_ptr;
89 UINT status;
90
91 /* Get the condition variable's internal semaphore. */
92 /* Simply convert the COndition variable control block into a semaphore a cast */
93 semaphore_ptr = (&( cond->cond_semaphore ));
94 if ( semaphore_ptr->tx_semaphore_suspended_count)
95 {
96 status = tx_semaphore_prioritize(semaphore_ptr);
97 if ( status != TX_SUCCESS)
98 {
99 posix_errno = EINVAL;
100 posix_set_pthread_errno(EINVAL);
101 return(EINVAL);
102 }
103 status = tx_semaphore_put(semaphore_ptr);
104 if ( status != TX_SUCCESS)
105 {
106 posix_errno = EINVAL;
107 posix_set_pthread_errno(EINVAL);
108 return(EINVAL);
109 }
110 }
111 return(OK);
112 }
113
