SDL  2.0
SDL_syscond.c
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
4 
5  This software is provided 'as-is', without any express or implied
6  warranty. In no event will the authors be held liable for any damages
7  arising from the use of this software.
8 
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12 
13  1. The origin of this software must not be misrepresented; you must not
14  claim that you wrote the original software. If you use this software
15  in a product, an acknowledgment in the product documentation would be
16  appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18  misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20 */
21 #include "../../SDL_internal.h"
22 
23 #include <sys/time.h>
24 #include <time.h>
25 #include <unistd.h>
26 #include <errno.h>
27 #include <pthread.h>
28 
29 #include "SDL_thread.h"
30 #include "SDL_sysmutex_c.h"
31 
32 struct SDL_cond
33 {
34  pthread_cond_t cond;
35 };
36 
37 /* Create a condition variable */
38 SDL_cond *
40 {
41  SDL_cond *cond;
42 
43  cond = (SDL_cond *) SDL_malloc(sizeof(SDL_cond));
44  if (cond) {
45  if (pthread_cond_init(&cond->cond, NULL) != 0) {
46  SDL_SetError("pthread_cond_init() failed");
47  SDL_free(cond);
48  cond = NULL;
49  }
50  }
51  return (cond);
52 }
53 
54 /* Destroy a condition variable */
55 void
57 {
58  if (cond) {
59  pthread_cond_destroy(&cond->cond);
60  SDL_free(cond);
61  }
62 }
63 
64 /* Restart one of the threads that are waiting on the condition variable */
65 int
67 {
68  int retval;
69 
70  if (!cond) {
71  return SDL_SetError("Passed a NULL condition variable");
72  }
73 
74  retval = 0;
75  if (pthread_cond_signal(&cond->cond) != 0) {
76  return SDL_SetError("pthread_cond_signal() failed");
77  }
78  return retval;
79 }
80 
81 /* Restart all threads that are waiting on the condition variable */
82 int
84 {
85  int retval;
86 
87  if (!cond) {
88  return SDL_SetError("Passed a NULL condition variable");
89  }
90 
91  retval = 0;
92  if (pthread_cond_broadcast(&cond->cond) != 0) {
93  return SDL_SetError("pthread_cond_broadcast() failed");
94  }
95  return retval;
96 }
97 
98 int
100 {
101  int retval;
102 #ifndef HAVE_CLOCK_GETTIME
103  struct timeval delta;
104 #endif
105  struct timespec abstime;
106 
107  if (!cond) {
108  return SDL_SetError("Passed a NULL condition variable");
109  }
110 
111 #ifdef HAVE_CLOCK_GETTIME
112  clock_gettime(CLOCK_REALTIME, &abstime);
113 
114  abstime.tv_nsec += (ms % 1000) * 1000000;
115  abstime.tv_sec += ms / 1000;
116 #else
117  gettimeofday(&delta, NULL);
118 
119  abstime.tv_sec = delta.tv_sec + (ms / 1000);
120  abstime.tv_nsec = (delta.tv_usec + (ms % 1000) * 1000) * 1000;
121 #endif
122  if (abstime.tv_nsec > 1000000000) {
123  abstime.tv_sec += 1;
124  abstime.tv_nsec -= 1000000000;
125  }
126 
127  tryagain:
128  retval = pthread_cond_timedwait(&cond->cond, &mutex->id, &abstime);
129  switch (retval) {
130  case EINTR:
131  goto tryagain;
132  /* break; -Wunreachable-code-break */
133  case ETIMEDOUT:
134  retval = SDL_MUTEX_TIMEDOUT;
135  break;
136  case 0:
137  break;
138  default:
139  retval = SDL_SetError("pthread_cond_timedwait() failed");
140  }
141  return retval;
142 }
143 
144 /* Wait on the condition variable, unlocking the provided mutex.
145  The mutex must be locked before entering this function!
146  */
147 int
149 {
150  if (!cond) {
151  return SDL_SetError("Passed a NULL condition variable");
152  } else if (pthread_cond_wait(&cond->cond, &mutex->id) != 0) {
153  return SDL_SetError("pthread_cond_wait() failed");
154  }
155  return 0;
156 }
157 
158 /* vi: set ts=4 sw=4 expandtab: */
int SDL_CondWait(SDL_cond *cond, SDL_mutex *mutex)
Definition: SDL_syscond.c:215
uint32_t Uint32
Definition: SDL_stdinc.h:181
static SDL_mutex * mutex
Definition: testlock.c:23
#define SDL_MUTEX_TIMEDOUT
Definition: SDL_mutex.h:44
SDL_cond * SDL_CreateCond(void)
Definition: SDL_syscond.c:42
SDL_bool retval
#define SDL_free
pthread_cond_t cond
Definition: SDL_syscond.c:34
#define NULL
Definition: begin_code.h:164
int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms)
Definition: SDL_syscond.c:160
#define SDL_SetError
#define SDL_malloc
pthread_mutex_t id
Definition: SDL_sysmutex.c:35
int SDL_CondBroadcast(SDL_cond *cond)
Definition: SDL_syscond.c:106
int SDL_CondSignal(SDL_cond *cond)
Definition: SDL_syscond.c:82
void SDL_DestroyCond(SDL_cond *cond)
Definition: SDL_syscond.c:64