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IlmThreadSemaphore.h
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34 
35 #ifndef INCLUDED_ILM_THREAD_SEMAPHORE_H
36 #define INCLUDED_ILM_THREAD_SEMAPHORE_H
37 
38 //-----------------------------------------------------------------------------
39 //
40 // class Semaphore -- a wrapper class for
41 // system-dependent counting semaphores
42 //
43 //-----------------------------------------------------------------------------
44 
45 #include "IlmBaseConfig.h"
46 #include "IlmThreadExport.h"
47 #include "IlmThreadNamespace.h"
48 
49 #if defined _WIN32 || defined _WIN64
50  #ifdef NOMINMAX
51  #undef NOMINMAX
52  #endif
53  #define NOMINMAX
54  #include <windows.h>
55 #elif HAVE_PTHREAD && !HAVE_POSIX_SEMAPHORES
56  #include <pthread.h>
57 #elif HAVE_PTHREAD && HAVE_POSIX_SEMAPHORES
58  #include <semaphore.h>
59 #endif
60 
62 
63 
65 {
66  public:
67 
68  Semaphore (unsigned int value = 0);
69  virtual ~Semaphore();
70 
71  void wait();
72  bool tryWait();
73  void post();
74  int value() const;
75 
76  private:
77 
78  #if defined _WIN32 || defined _WIN64
79 
80  mutable HANDLE _semaphore;
81 
82  #elif HAVE_PTHREAD && !HAVE_POSIX_SEMAPHORES
83 
84  //
85  // If the platform has Posix threads but no semapohores,
86  // then we implement them ourselves using condition variables
87  //
88 
89  struct sema_t
90  {
91  unsigned int count;
92  unsigned long numWaiting;
93  pthread_mutex_t mutex;
94  pthread_cond_t nonZero;
95  };
96 
97  mutable sema_t _semaphore;
98 
99  #elif HAVE_PTHREAD && HAVE_POSIX_SEMAPHORES
100 
101  mutable sem_t _semaphore;
102 
103  #endif
104 
105  void operator = (const Semaphore& s); // not implemented
106  Semaphore (const Semaphore& s); // not implemented
107 };
108 
109 
111 
112 #endif // INCLUDED_ILM_THREAD_SEMAPHORE_H
#define ILMTHREAD_INTERNAL_NAMESPACE_HEADER_ENTER
#define ILMTHREAD_INTERNAL_NAMESPACE_HEADER_EXIT
#define ILMTHREAD_EXPORT
GLint GLsizei count
Definition: glcorearb.h:404
GLsizei const GLfloat * value
Definition: glcorearb.h:823