xref: /trunk/main/sal/inc/internal/once.h (revision fc9fd3f14a55d77b35643a64034752a178b2a5b0)
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27 
28 #ifndef INCLUDED_SAL_INTERNAL_ONCE_H
29 #define INCLUDED_SAL_INTERNAL_ONCE_H
30 
31 /** sal_once_type
32  *  (platform dependent)
33  */
34 
35 #if defined(SAL_UNX) || defined(SAL_OS2)
36 
37 #include <pthread.h>
38 
39 typedef pthread_once_t sal_once_type;
40 
41 #define SAL_ONCE_INIT PTHREAD_ONCE_INIT
42 #define SAL_ONCE(once, init) pthread_once((once), (init))
43 
44 #elif defined(SAL_W32)
45 
46 #define WIN32_LEAN_AND_MEAN
47 #pragma warning(push,1) /* disable warnings within system headers */
48 #include <windows.h>
49 #pragma warning(pop)
50 
51 typedef struct sal_once_st sal_once_type;
52 struct sal_once_st
53 {
54     LONG volatile m_done;
55     LONG volatile m_lock;
56 };
57 
58 #define SAL_ONCE_INIT { 0, 0 }
59 #define SAL_ONCE(once, init) \
60 { \
61     sal_once_type * control = (once); \
62     if (!(control->m_done)) \
63     { \
64         while (InterlockedExchange(&(control->m_lock), 1) == 1) Sleep(0); \
65         if (!(control->m_done)) \
66         { \
67             void (*init_routine)(void) = (init); \
68             (*init_routine)(); \
69             control->m_done = 1; \
70         } \
71         InterlockedExchange(&(control->m_lock), 0); \
72     } \
73 }
74 
75 #else
76 #error Unknown platform
77 #endif /* SAL_UNX | SAL_W32 */
78 
79 #endif /* INCLUDED_SAL_INTERNAL_ONCE_H */
80