2 * C11 <threads.h> emulation library
4 * (C) Copyright yohhoy 2012.
5 * Distributed under the Boost Software License, Version 1.0.
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34 #include <process.h> // MSVCRT
40 EMULATED_THREADS_USE_NATIVE_CALL_ONCE
41 Use native WindowsAPI one-time initialization function.
42 (requires WinVista or later)
43 Otherwise emulate by mtx_trylock() + *busy loop* for WinXP.
45 EMULATED_THREADS_USE_NATIVE_CV
46 Use native WindowsAPI condition variable object.
47 (requires WinVista or later)
48 Otherwise use emulated implementation for WinXP.
50 EMULATED_THREADS_TSS_DTOR_SLOTNUM
51 Max registerable TSS dtor number.
54 // XXX: Retain XP compatability
56 #if _WIN32_WINNT >= 0x0600
57 // Prefer native WindowsAPI on newer environment.
58 #if !defined(__MINGW32__)
59 #define EMULATED_THREADS_USE_NATIVE_CALL_ONCE
61 #define EMULATED_THREADS_USE_NATIVE_CV
64 #define EMULATED_THREADS_TSS_DTOR_SLOTNUM 64 // see TLS_MINIMUM_AVAILABLE
69 // check configuration
70 #if defined(EMULATED_THREADS_USE_NATIVE_CALL_ONCE) && (_WIN32_WINNT < 0x0600)
71 #error EMULATED_THREADS_USE_NATIVE_CALL_ONCE requires _WIN32_WINNT>=0x0600
74 #if defined(EMULATED_THREADS_USE_NATIVE_CV) && (_WIN32_WINNT < 0x0600)
75 #error EMULATED_THREADS_USE_NATIVE_CV requires _WIN32_WINNT>=0x0600
79 /*---------------------------- macros ----------------------------*/
80 #ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
81 #define ONCE_FLAG_INIT INIT_ONCE_STATIC_INIT
83 #define ONCE_FLAG_INIT {0}
85 #define TSS_DTOR_ITERATIONS 1
87 // FIXME: temporary non-standard hack to ease transition
88 #define _MTX_INITIALIZER_NP {(PCRITICAL_SECTION_DEBUG)-1, -1, 0, 0, 0, 0}
90 /*---------------------------- types ----------------------------*/
91 typedef struct cnd_t
{
92 #ifdef EMULATED_THREADS_USE_NATIVE_CV
93 CONDITION_VARIABLE condvar
;
100 CRITICAL_SECTION monitor
;
104 typedef HANDLE thrd_t
;
108 typedef CRITICAL_SECTION mtx_t
;
110 #ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
111 typedef INIT_ONCE once_flag
;
113 typedef struct once_flag_t
{
114 volatile LONG status
;
119 static inline void * tss_get(tss_t key
);
120 static inline void thrd_yield(void);
121 static inline int mtx_trylock(mtx_t
*mtx
);
122 static inline int mtx_lock(mtx_t
*mtx
);
123 static inline int mtx_unlock(mtx_t
*mtx
);
126 Implementation limits:
127 - Conditionally emulation for "Initialization functions"
128 (see EMULATED_THREADS_USE_NATIVE_CALL_ONCE macro)
129 - Emulated `mtx_timelock()' with mtx_trylock() + *busy loop*
131 static void impl_tss_dtor_invoke(void); // forward decl.
133 struct impl_thrd_param
{
138 static unsigned __stdcall
impl_thrd_routine(void *p
)
140 struct impl_thrd_param pack
;
142 memcpy(&pack
, p
, sizeof(struct impl_thrd_param
));
144 code
= pack
.func(pack
.arg
);
145 impl_tss_dtor_invoke();
146 return (unsigned)code
;
149 static DWORD
impl_xtime2msec(const xtime
*xt
)
151 return (DWORD
)((xt
->sec
* 1000U) + (xt
->nsec
/ 1000000L));
154 #ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
155 struct impl_call_once_param
{ void (*func
)(void); };
156 static BOOL CALLBACK
impl_call_once_callback(PINIT_ONCE InitOnce
, PVOID Parameter
, PVOID
*Context
)
158 struct impl_call_once_param
*param
= (struct impl_call_once_param
*)Parameter
;
160 ((void)InitOnce
); ((void)Context
); // suppress warning
163 #endif // ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
165 #ifndef EMULATED_THREADS_USE_NATIVE_CV
168 The implementation of condition variable is ported from Boost.Interprocess
169 See http://www.boost.org/boost/interprocess/sync/windows/condition.hpp
171 static void impl_cond_do_signal(cnd_t
*cond
, int broadcast
)
175 EnterCriticalSection(&cond
->monitor
);
176 if (cond
->to_unblock
!= 0) {
177 if (cond
->blocked
== 0) {
178 LeaveCriticalSection(&cond
->monitor
);
182 cond
->to_unblock
+= nsignal
= cond
->blocked
;
189 } else if (cond
->blocked
> cond
->gone
) {
190 WaitForSingleObject(cond
->sem_gate
, INFINITE
);
191 if (cond
->gone
!= 0) {
192 cond
->blocked
-= cond
->gone
;
196 nsignal
= cond
->to_unblock
= cond
->blocked
;
199 nsignal
= cond
->to_unblock
= 1;
203 LeaveCriticalSection(&cond
->monitor
);
206 ReleaseSemaphore(cond
->sem_queue
, nsignal
, NULL
);
209 static int impl_cond_do_wait(cnd_t
*cond
, mtx_t
*mtx
, const xtime
*xt
)
216 WaitForSingleObject(cond
->sem_gate
, INFINITE
);
218 ReleaseSemaphore(cond
->sem_gate
, 1, NULL
);
222 w
= WaitForSingleObject(cond
->sem_queue
, xt
? impl_xtime2msec(xt
) : INFINITE
);
223 timeout
= (w
== WAIT_TIMEOUT
);
225 EnterCriticalSection(&cond
->monitor
);
226 if ((nleft
= cond
->to_unblock
) != 0) {
228 if (cond
->blocked
!= 0) {
234 if (--cond
->to_unblock
== 0) {
235 if (cond
->blocked
!= 0) {
236 ReleaseSemaphore(cond
->sem_gate
, 1, NULL
);
239 else if ((ngone
= cond
->gone
) != 0) {
243 } else if (++cond
->gone
== INT_MAX
/2) {
244 WaitForSingleObject(cond
->sem_gate
, INFINITE
);
245 cond
->blocked
-= cond
->gone
;
246 ReleaseSemaphore(cond
->sem_gate
, 1, NULL
);
249 LeaveCriticalSection(&cond
->monitor
);
253 WaitForSingleObject(cond
->sem_queue
, INFINITE
);
254 ReleaseSemaphore(cond
->sem_gate
, 1, NULL
);
258 return timeout
? thrd_busy
: thrd_success
;
260 #endif // ifndef EMULATED_THREADS_USE_NATIVE_CV
262 static struct impl_tss_dtor_entry
{
265 } impl_tss_dtor_tbl
[EMULATED_THREADS_TSS_DTOR_SLOTNUM
];
267 static int impl_tss_dtor_register(tss_t key
, tss_dtor_t dtor
)
270 for (i
= 0; i
< EMULATED_THREADS_TSS_DTOR_SLOTNUM
; i
++) {
271 if (!impl_tss_dtor_tbl
[i
].dtor
)
274 if (i
== EMULATED_THREADS_TSS_DTOR_SLOTNUM
)
276 impl_tss_dtor_tbl
[i
].key
= key
;
277 impl_tss_dtor_tbl
[i
].dtor
= dtor
;
281 static void impl_tss_dtor_invoke()
284 for (i
= 0; i
< EMULATED_THREADS_TSS_DTOR_SLOTNUM
; i
++) {
285 if (impl_tss_dtor_tbl
[i
].dtor
) {
286 void* val
= tss_get(impl_tss_dtor_tbl
[i
].key
);
288 (impl_tss_dtor_tbl
[i
].dtor
)(val
);
294 /*--------------- 7.25.2 Initialization functions ---------------*/
297 call_once(once_flag
*flag
, void (*func
)(void))
299 assert(flag
&& func
);
300 #ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
302 struct impl_call_once_param param
;
304 InitOnceExecuteOnce(flag
, impl_call_once_callback
, (PVOID
)¶m
, NULL
);
307 if (InterlockedCompareExchange(&flag
->status
, 1, 0) == 0) {
309 InterlockedExchange(&flag
->status
, 2);
311 while (flag
->status
== 1) {
320 /*------------- 7.25.3 Condition variable functions -------------*/
323 cnd_broadcast(cnd_t
*cond
)
325 if (!cond
) return thrd_error
;
326 #ifdef EMULATED_THREADS_USE_NATIVE_CV
327 WakeAllConditionVariable(&cond
->condvar
);
329 impl_cond_do_signal(cond
, 1);
336 cnd_destroy(cnd_t
*cond
)
339 #ifdef EMULATED_THREADS_USE_NATIVE_CV
342 CloseHandle(cond
->sem_queue
);
343 CloseHandle(cond
->sem_gate
);
344 DeleteCriticalSection(&cond
->monitor
);
350 cnd_init(cnd_t
*cond
)
352 if (!cond
) return thrd_error
;
353 #ifdef EMULATED_THREADS_USE_NATIVE_CV
354 InitializeConditionVariable(&cond
->condvar
);
358 cond
->to_unblock
= 0;
359 cond
->sem_queue
= CreateSemaphore(NULL
, 0, LONG_MAX
, NULL
);
360 cond
->sem_gate
= CreateSemaphore(NULL
, 1, 1, NULL
);
361 InitializeCriticalSection(&cond
->monitor
);
368 cnd_signal(cnd_t
*cond
)
370 if (!cond
) return thrd_error
;
371 #ifdef EMULATED_THREADS_USE_NATIVE_CV
372 WakeConditionVariable(&cond
->condvar
);
374 impl_cond_do_signal(cond
, 0);
381 cnd_timedwait(cnd_t
*cond
, mtx_t
*mtx
, const xtime
*xt
)
383 if (!cond
|| !mtx
|| !xt
) return thrd_error
;
384 #ifdef EMULATED_THREADS_USE_NATIVE_CV
385 if (SleepConditionVariableCS(&cond
->condvar
, mtx
, impl_xtime2msec(xt
)))
387 return (GetLastError() == ERROR_TIMEOUT
) ? thrd_busy
: thrd_error
;
389 return impl_cond_do_wait(cond
, mtx
, xt
);
395 cnd_wait(cnd_t
*cond
, mtx_t
*mtx
)
397 if (!cond
|| !mtx
) return thrd_error
;
398 #ifdef EMULATED_THREADS_USE_NATIVE_CV
399 SleepConditionVariableCS(&cond
->condvar
, mtx
, INFINITE
);
401 impl_cond_do_wait(cond
, mtx
, NULL
);
407 /*-------------------- 7.25.4 Mutex functions --------------------*/
410 mtx_destroy(mtx_t
*mtx
)
413 DeleteCriticalSection(mtx
);
418 mtx_init(mtx_t
*mtx
, int type
)
420 if (!mtx
) return thrd_error
;
421 if (type
!= mtx_plain
&& type
!= mtx_timed
&& type
!= mtx_try
422 && type
!= (mtx_plain
|mtx_recursive
)
423 && type
!= (mtx_timed
|mtx_recursive
)
424 && type
!= (mtx_try
|mtx_recursive
))
426 InitializeCriticalSection(mtx
);
434 if (!mtx
) return thrd_error
;
435 EnterCriticalSection(mtx
);
441 mtx_timedlock(mtx_t
*mtx
, const xtime
*xt
)
444 if (!mtx
|| !xt
) return thrd_error
;
447 while (mtx_trylock(mtx
) != thrd_success
) {
459 mtx_trylock(mtx_t
*mtx
)
461 if (!mtx
) return thrd_error
;
462 return TryEnterCriticalSection(mtx
) ? thrd_success
: thrd_busy
;
467 mtx_unlock(mtx_t
*mtx
)
469 if (!mtx
) return thrd_error
;
470 LeaveCriticalSection(mtx
);
475 /*------------------- 7.25.5 Thread functions -------------------*/
478 thrd_create(thrd_t
*thr
, thrd_start_t func
, void *arg
)
480 struct impl_thrd_param
*pack
;
482 if (!thr
) return thrd_error
;
483 pack
= (struct impl_thrd_param
*)malloc(sizeof(struct impl_thrd_param
));
484 if (!pack
) return thrd_nomem
;
487 handle
= _beginthreadex(NULL
, 0, impl_thrd_routine
, pack
, 0, NULL
);
489 if (errno
== EAGAIN
|| errno
== EACCES
)
493 *thr
= (thrd_t
)handle
;
502 HANDLE hCurrentThread
;
505 /* GetCurrentThread() returns a pseudo-handle, which is useless. We need
506 * to call DuplicateHandle to get a real handle. However the handle value
507 * will not match the one returned by thread_create.
509 * Other potential solutions would be:
510 * - define thrd_t as a thread Ids, but this would mean we'd need to OpenThread for many operations
511 * - use malloc'ed memory for thrd_t. This would imply using TLS for current thread.
513 * Neither is particularly nice.
515 * Life would be much easier if C11 threads had different abstractions for
516 * threads and thread IDs, just like C++11 threads does...
519 bRet
= DuplicateHandle(GetCurrentProcess(), // source process (pseudo) handle
520 GetCurrentThread(), // source (pseudo) handle
521 GetCurrentProcess(), // target process
522 &hCurrentThread
, // target handle
525 DUPLICATE_SAME_ACCESS
);
528 hCurrentThread
= GetCurrentThread();
530 return hCurrentThread
;
536 thrd_detach(thrd_t thr
)
544 thrd_equal(thrd_t thr0
, thrd_t thr1
)
546 return GetThreadId(thr0
) == GetThreadId(thr1
);
553 impl_tss_dtor_invoke();
554 _endthreadex((unsigned)res
);
559 thrd_join(thrd_t thr
, int *res
)
562 w
= WaitForSingleObject(thr
, INFINITE
);
563 if (w
!= WAIT_OBJECT_0
)
566 if (!GetExitCodeThread(thr
, &code
)) {
578 thrd_sleep(const xtime
*xt
)
581 Sleep(impl_xtime2msec(xt
));
592 /*----------- 7.25.6 Thread-specific storage functions -----------*/
595 tss_create(tss_t
*key
, tss_dtor_t dtor
)
597 if (!key
) return thrd_error
;
600 if (impl_tss_dtor_register(*key
, dtor
)) {
605 return (*key
!= 0xFFFFFFFF) ? thrd_success
: thrd_error
;
610 tss_delete(tss_t key
)
619 return TlsGetValue(key
);
624 tss_set(tss_t key
, void *val
)
626 return TlsSetValue(key
, val
) ? thrd_success
: thrd_error
;
630 /*-------------------- 7.25.7 Time functions --------------------*/
633 xtime_get(xtime
*xt
, int base
)
636 if (base
== TIME_UTC
) {
637 xt
->sec
= time(NULL
);