SDL  2.0
SDL_systls.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 
22 #include "../../SDL_internal.h"
23 
24 #if SDL_THREAD_WINDOWS
25 
26 #include "../../core/windows/SDL_windows.h"
27 
28 #include "SDL_thread.h"
29 #include "../SDL_thread_c.h"
30 
31 static DWORD thread_local_storage = TLS_OUT_OF_INDEXES;
32 static SDL_bool generic_local_storage = SDL_FALSE;
33 
34 SDL_TLSData *
35 SDL_SYS_GetTLSData(void)
36 {
37  if (thread_local_storage == TLS_OUT_OF_INDEXES && !generic_local_storage) {
38  static SDL_SpinLock lock;
39  SDL_AtomicLock(&lock);
40  if (thread_local_storage == TLS_OUT_OF_INDEXES && !generic_local_storage) {
41  DWORD storage = TlsAlloc();
42  if (storage != TLS_OUT_OF_INDEXES) {
43  SDL_MemoryBarrierRelease();
44  thread_local_storage = storage;
45  } else {
46  generic_local_storage = SDL_TRUE;
47  }
48  }
49  SDL_AtomicUnlock(&lock);
50  }
51  if (generic_local_storage) {
52  return SDL_Generic_GetTLSData();
53  }
54  SDL_MemoryBarrierAcquire();
55  return (SDL_TLSData *)TlsGetValue(thread_local_storage);
56 }
57 
58 int
59 SDL_SYS_SetTLSData(SDL_TLSData *data)
60 {
61  if (generic_local_storage) {
62  return SDL_Generic_SetTLSData(data);
63  }
64  if (!TlsSetValue(thread_local_storage, data)) {
65  return SDL_SetError("TlsSetValue() failed");
66  }
67  return 0;
68 }
69 
70 #endif /* SDL_THREAD_WINDOWS */
71 
72 /* vi: set ts=4 sw=4 expandtab: */