Implemented SDL_SetThreadPriority()

include/SDL_thread.h

@@ -50,6 +50,16 @@ typedef struct SDL_Thread SDL_Thread;
 /* The SDL thread ID */
 typedef unsigned long SDL_threadID;
 
+/* The SDL thread priority
+ *
+ * Note: On many systems you require special privileges to set high priority.
+ */
+typedef enum {
+    SDL_THREAD_PRIORITY_LOW,
+    SDL_THREAD_PRIORITY_NORMAL,
+    SDL_THREAD_PRIORITY_HIGH
+} SDL_ThreadPriority;
+
 /* The function passed to SDL_CreateThread()
    It is passed a void* user context parameter and returns an int.
  */
@@ -146,6 +156,11 @@ extern DECLSPEC SDL_threadID SDLCALL SDL_ThreadID(void);
  */
 extern DECLSPEC SDL_threadID SDLCALL SDL_GetThreadID(SDL_Thread * thread);
 
+/**
+ *  Set the thread priority
+ */
+extern DECLSPEC int SDLCALL SDL_SetThreadPriority(SDL_Thread * thread, SDL_ThreadPriority priority);
+
 /**
  *  Wait for a thread to finish.
  *  

src/audio/SDL_audio.c

@@ -974,6 +974,7 @@ open_audio_device(const char *devname, int iscapture,
             SDL_SetError("Couldn't create audio thread");
             return 0;
         }
+        SDL_SetThreadPriority(device->thread, SDL_THREAD_PRIORITY_HIGH);
     }
 
     return id + 1;

src/thread/SDL_systhread.h

@@ -43,6 +43,9 @@ extern int SDL_SYS_CreateThread(SDL_Thread * thread, void *args);
 /* This function does any necessary setup in the child thread */
 extern void SDL_SYS_SetupThread(void);
 
+/* This function sets thread priority */
+extern int SDL_SYS_SetThreadPriority(SDL_Thread * thread, SDL_ThreadPriority priority);
+
 /* This function waits for the thread to finish and frees any data
    allocated by SDL_SYS_CreateThread()
  */

src/thread/SDL_thread.c

@@ -281,19 +281,6 @@ SDL_CreateThread(int (SDLCALL * fn) (void *), void *data)
     return (thread);
 }
 
-void
-SDL_WaitThread(SDL_Thread * thread, int *status)
-{
-    if (thread) {
-        SDL_SYS_WaitThread(thread);
-        if (status) {
-            *status = thread->status;
-        }
-        SDL_DelThread(thread);
-        SDL_free(thread);
-    }
-}
-
 SDL_threadID
 SDL_GetThreadID(SDL_Thread * thread)
 {
@@ -307,4 +294,27 @@ SDL_GetThreadID(SDL_Thread * thread)
     return id;
 }
 
+int
+SDL_SetThreadPriority(SDL_Thread * thread, SDL_ThreadPriority priority)
+{
+    if (!thread) {
+        SDL_SetError("SDL_SetThreadPriority() passed NULL thread");
+        return -1;
+    }
+    return SDL_SYS_SetThreadPriority(thread, priority);
+}
+
+void
+SDL_WaitThread(SDL_Thread * thread, int *status)
+{
+    if (thread) {
+        SDL_SYS_WaitThread(thread);
+        if (status) {
+            *status = thread->status;
+        }
+        SDL_DelThread(thread);
+        SDL_free(thread);
+    }
+}
+
 /* vi: set ts=4 sw=4 expandtab: */

src/thread/beos/SDL_systhread.c

@@ -90,6 +90,20 @@ SDL_ThreadID(void)
     return ((SDL_threadID) find_thread(NULL));
 }
 
+int
+SDL_SYS_SetThreadPriority(SDL_Thread * thread, SDL_ThreadPriority priority)
+{
+    int32 new_priority = B_NORMAL_PRIORITY;
+
+    if (priority == SDL_THREAD_PRIORITY_LOW) {
+        new_priority = B_LOW_PRIORITY;
+    } else if (priority == SDL_THREAD_PRIORITY_HIGH) {
+        new_priority = B_URGENT_DISPLAY_PRIORITY;
+    }
+    set_thread_priority(thread->handle, new_priority);
+    return 0;
+}
+
 void
 SDL_SYS_WaitThread(SDL_Thread * thread)
 {

src/thread/generic/SDL_systhread.c

@@ -45,6 +45,12 @@ SDL_ThreadID(void)
     return (0);
 }
 
+int
+SDL_SYS_SetThreadPriority(SDL_Thread * thread, SDL_ThreadPriority priority)
+{
+    return (0);
+}
+
 void
 SDL_SYS_WaitThread(SDL_Thread * thread)
 {

src/thread/nds/SDL_syscond.c

@@ -227,3 +227,5 @@ SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex)
 {
     return SDL_CondWaitTimeout(cond, mutex, SDL_MUTEX_MAXWAIT);
 }
+
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/nds/SDL_sysmutex.c

@@ -140,3 +140,5 @@ SDL_mutexV(SDL_mutex * mutex)
     return 0;
 #endif /* DISABLE_THREADS */
 }
+
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/nds/SDL_syssem.c

@@ -226,3 +226,5 @@ SDL_SemPost(SDL_sem * sem)
 }
 
 #endif /* DISABLE_THREADS */
+
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/nds/SDL_systhread.c

@@ -56,8 +56,16 @@ SDL_SYS_WaitThread(SDL_Thread * thread)
     return;
 }
 
+int
+SDL_SYS_SetThreadPriority(SDL_Thread * thread, SDL_ThreadPriority priority)
+{
+    return (0);
+}
+
 void
 SDL_SYS_KillThread(SDL_Thread * thread)
 {
     return;
 }
+
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/pthread/SDL_systhread.c

@@ -91,6 +91,33 @@ SDL_ThreadID(void)
     return ((SDL_threadID) pthread_self());
 }
 
+int
+SDL_SYS_SetThreadPriority(SDL_Thread * thread, SDL_ThreadPriority priority)
+{
+    struct sched_param sched;
+    int policy;
+
+    if (pthread_getschedparam(thread->handle, &policy, &sched) < 0) {
+        SDL_SetError("pthread_getschedparam() failed");
+        return -1;
+    }
+    if (priority == SDL_THREAD_PRIORITY_LOW) {
+        sched.sched_priority = sched_get_priority_min(policy);
+    } else if (priority == SDL_THREAD_PRIORITY_HIGH) {
+        sched.sched_priority = sched_get_priority_max(policy);
+    } else {
+        int min_priority = sched_get_priority_min(policy);
+        int max_priority = sched_get_priority_max(policy);
+        int priority = (min_priority + (max_priority - min_priority) / 2);
+        sched.sched_priority = priority;
+    }
+    if (pthread_setschedparam(thread->handle, policy, &sched) < 0) {
+        SDL_SetError("pthread_setschedparam() failed");
+        return -1;
+    }
+    return 0;
+}
+
 void
 SDL_SYS_WaitThread(SDL_Thread * thread)
 {

src/thread/windows/SDL_systhread.c

@@ -155,6 +155,25 @@ SDL_ThreadID(void)
     return ((SDL_threadID) GetCurrentThreadId());
 }
 
+int
+SDL_SYS_SetThreadPriority(SDL_Thread * thread, SDL_ThreadPriority priority)
+{
+    BOOL result;
+
+    if (priority == SDL_THREAD_PRIORITY_LOW) {
+        result = SetThreadPriority(thread->handle, THREAD_PRIORITY_LOWEST);
+    } else if (priority == SDL_THREAD_PRIORITY_HIGH) {
+        result = SetThreadPriority(thread->handle, THREAD_PRIORITY_HIGHEST);
+    } else {
+        result = SetThreadPriority(thread->handle, THREAD_PRIORITY_NORMAL);
+    }
+    if (!result) {
+        WIN_SetError("SetThreadPriority()");
+        return -1;
+    }
+    return 0;
+}
+
 void
 SDL_SYS_WaitThread(SDL_Thread * thread)
 {