SDL  2.0
SDL_sysmutex.c File Reference
#include "../../SDL_internal.h"
#include <errno.h>
#include <pthread.h>
#include "SDL_thread.h"
+ Include dependency graph for SDL_sysmutex.c:

Go to the source code of this file.

Data Structures

struct  SDL_mutex
 

Macros

#define FAKE_RECURSIVE_MUTEX   1
 

Functions

SDL_mutexSDL_CreateMutex (void)
 
void SDL_DestroyMutex (SDL_mutex *mutex)
 
int SDL_LockMutex (SDL_mutex *mutex)
 
int SDL_TryLockMutex (SDL_mutex *mutex)
 
int SDL_UnlockMutex (SDL_mutex *mutex)
 

Macro Definition Documentation

#define FAKE_RECURSIVE_MUTEX   1

Definition at line 30 of file SDL_sysmutex.c.

Function Documentation

SDL_mutex* SDL_CreateMutex ( void  )

Create a mutex, initialized unlocked.

Definition at line 43 of file SDL_sysmutex.c.

References SDL_mutex::id, mutex, NULL, SDL_calloc, SDL_free, SDL_OutOfMemory, and SDL_SetError.

44 {
46  pthread_mutexattr_t attr;
47 
48  /* Allocate the structure */
49  mutex = (SDL_mutex *) SDL_calloc(1, sizeof(*mutex));
50  if (mutex) {
51  pthread_mutexattr_init(&attr);
52 #if SDL_THREAD_PTHREAD_RECURSIVE_MUTEX
53  pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
54 #elif SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
55  pthread_mutexattr_setkind_np(&attr, PTHREAD_MUTEX_RECURSIVE_NP);
56 #else
57  /* No extra attributes necessary */
58 #endif
59  if (pthread_mutex_init(&mutex->id, &attr) != 0) {
60  SDL_SetError("pthread_mutex_init() failed");
61  SDL_free(mutex);
62  mutex = NULL;
63  }
64  } else {
66  }
67  return (mutex);
68 }
static SDL_mutex * mutex
Definition: testlock.c:23
#define SDL_free
#define NULL
Definition: begin_code.h:164
#define SDL_OutOfMemory()
Definition: SDL_error.h:52
#define SDL_SetError
#define SDL_calloc
pthread_mutex_t id
Definition: SDL_sysmutex.c:35
void SDL_DestroyMutex ( SDL_mutex mutex)

Destroy a mutex.

Definition at line 71 of file SDL_sysmutex.c.

References SDL_mutex::id, and SDL_free.

72 {
73  if (mutex) {
74  pthread_mutex_destroy(&mutex->id);
75  SDL_free(mutex);
76  }
77 }
#define SDL_free
pthread_mutex_t id
Definition: SDL_sysmutex.c:35
int SDL_LockMutex ( SDL_mutex mutex)

Definition at line 81 of file SDL_sysmutex.c.

References SDL_mutex::id, NULL, SDL_mutex::owner, SDL_mutex::recursive, and SDL_SetError.

82 {
83 #if FAKE_RECURSIVE_MUTEX
84  pthread_t this_thread;
85 #endif
86 
87  if (mutex == NULL) {
88  return SDL_SetError("Passed a NULL mutex");
89  }
90 
91 #if FAKE_RECURSIVE_MUTEX
92  this_thread = pthread_self();
93  if (mutex->owner == this_thread) {
94  ++mutex->recursive;
95  } else {
96  /* The order of operations is important.
97  We set the locking thread id after we obtain the lock
98  so unlocks from other threads will fail.
99  */
100  if (pthread_mutex_lock(&mutex->id) == 0) {
101  mutex->owner = this_thread;
102  mutex->recursive = 0;
103  } else {
104  return SDL_SetError("pthread_mutex_lock() failed");
105  }
106  }
107 #else
108  if (pthread_mutex_lock(&mutex->id) != 0) {
109  return SDL_SetError("pthread_mutex_lock() failed");
110  }
111 #endif
112  return 0;
113 }
#define NULL
Definition: begin_code.h:164
#define SDL_SetError
SDL_threadID owner
Definition: SDL_sysmutex.c:32
int recursive
Definition: SDL_sysmutex.c:31
pthread_mutex_t id
Definition: SDL_sysmutex.c:35
int SDL_TryLockMutex ( SDL_mutex mutex)

Try to lock the mutex

Returns
0, SDL_MUTEX_TIMEDOUT, or -1 on error

Definition at line 116 of file SDL_sysmutex.c.

References SDL_mutex::id, NULL, SDL_mutex::owner, SDL_mutex::recursive, retval, SDL_MUTEX_TIMEDOUT, and SDL_SetError.

117 {
118  int retval;
119  int result;
120 #if FAKE_RECURSIVE_MUTEX
121  pthread_t this_thread;
122 #endif
123 
124  if (mutex == NULL) {
125  return SDL_SetError("Passed a NULL mutex");
126  }
127 
128  retval = 0;
129 #if FAKE_RECURSIVE_MUTEX
130  this_thread = pthread_self();
131  if (mutex->owner == this_thread) {
132  ++mutex->recursive;
133  } else {
134  /* The order of operations is important.
135  We set the locking thread id after we obtain the lock
136  so unlocks from other threads will fail.
137  */
138  result = pthread_mutex_trylock(&mutex->id);
139  if (result == 0) {
140  mutex->owner = this_thread;
141  mutex->recursive = 0;
142  } else if (result == EBUSY) {
143  retval = SDL_MUTEX_TIMEDOUT;
144  } else {
145  retval = SDL_SetError("pthread_mutex_trylock() failed");
146  }
147  }
148 #else
149  result = pthread_mutex_trylock(&mutex->id);
150  if (result != 0) {
151  if (result == EBUSY) {
152  retval = SDL_MUTEX_TIMEDOUT;
153  } else {
154  retval = SDL_SetError("pthread_mutex_trylock() failed");
155  }
156  }
157 #endif
158  return retval;
159 }
GLuint64EXT * result
#define SDL_MUTEX_TIMEDOUT
Definition: SDL_mutex.h:44
SDL_bool retval
#define NULL
Definition: begin_code.h:164
#define SDL_SetError
SDL_threadID owner
Definition: SDL_sysmutex.c:32
int recursive
Definition: SDL_sysmutex.c:31
pthread_mutex_t id
Definition: SDL_sysmutex.c:35
int SDL_UnlockMutex ( SDL_mutex mutex)

Definition at line 162 of file SDL_sysmutex.c.

References SDL_mutex::id, NULL, SDL_mutex::owner, SDL_mutex::recursive, and SDL_SetError.

163 {
164  if (mutex == NULL) {
165  return SDL_SetError("Passed a NULL mutex");
166  }
167 
168 #if FAKE_RECURSIVE_MUTEX
169  /* We can only unlock the mutex if we own it */
170  if (pthread_self() == mutex->owner) {
171  if (mutex->recursive) {
172  --mutex->recursive;
173  } else {
174  /* The order of operations is important.
175  First reset the owner so another thread doesn't lock
176  the mutex and set the ownership before we reset it,
177  then release the lock semaphore.
178  */
179  mutex->owner = 0;
180  pthread_mutex_unlock(&mutex->id);
181  }
182  } else {
183  return SDL_SetError("mutex not owned by this thread");
184  }
185 
186 #else
187  if (pthread_mutex_unlock(&mutex->id) != 0) {
188  return SDL_SetError("pthread_mutex_unlock() failed");
189  }
190 #endif /* FAKE_RECURSIVE_MUTEX */
191 
192  return 0;
193 }
#define NULL
Definition: begin_code.h:164
#define SDL_SetError
SDL_threadID owner
Definition: SDL_sysmutex.c:32
int recursive
Definition: SDL_sysmutex.c:31
pthread_mutex_t id
Definition: SDL_sysmutex.c:35