1 #ifndef CYGONCE_KERNEL_SEMA_HXX
2 #define CYGONCE_KERNEL_SEMA_HXX
4 //==========================================================================
8 // Semaphore class declarations
10 //==========================================================================
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41 // -------------------------------------------
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43 //==========================================================================
44 //#####DESCRIPTIONBEGIN####
47 // Contributors: nickg
49 // Purpose: Define Semaphore class interfaces
50 // Description: The classes defined here provide the APIs for binary
51 // and counting semaphores.
52 // Usage: #include <cyg/kernel/sema.hxx>
55 //####DESCRIPTIONEND####
57 //==========================================================================
59 #include <cyg/kernel/ktypes.h>
60 #include <cyg/infra/cyg_ass.h> // assertion macros
61 #include <cyg/kernel/thread.inl> // thread inlines
63 // -------------------------------------------------------------------------
64 // Binary semaphore. This has only two states: posted and not-posted.
66 class Cyg_Binary_Semaphore
68 cyg_bool state; // The binary semaphore state
70 Cyg_ThreadQueue queue; // Queue of waiting threads
74 CYGDBG_DEFINE_CHECK_THIS
76 Cyg_Binary_Semaphore( // Constructor
77 cyg_bool init_state = false // Initial state value
80 ~Cyg_Binary_Semaphore(); // Destructor
82 cyg_bool wait(); // Wait until state == true
84 #ifdef CYGFUN_KERNEL_THREADS_TIMER
85 cyg_bool wait( cyg_tick_count timeout );
86 #endif // Wait until state == true or timeout
88 cyg_bool trywait(); // Set state false if possible
90 void post(); // Increment count
92 cyg_bool posted(); // Get current state
96 // -------------------------------------------------------------------------
97 // Counting semaphore. This implements the usual counter based semaphore.
99 class Cyg_Counting_Semaphore
101 cyg_count32 count; // The semaphore count
103 Cyg_ThreadQueue queue; // Queue of waiting threads
107 CYGDBG_DEFINE_CHECK_THIS
109 Cyg_Counting_Semaphore( // Constructor
110 cyg_count32 init_count = 0 // Initial count value
113 ~Cyg_Counting_Semaphore(); // Destructor
115 cyg_bool wait(); // Wait until decrement
117 #ifdef CYGFUN_KERNEL_THREADS_TIMER
118 cyg_bool wait( cyg_tick_count timeout );
119 #endif // Wait until decrement or timeout
121 cyg_bool trywait(); // Try to decrement
123 void post(); // Increment count
125 cyg_count32 peek() const; // Get current count value
128 cyg_bool waiting() // Is anyone waiting?
130 return !queue.empty();
135 // -------------------------------------------------------------------------
136 #endif // ifndef CYGONCE_KERNEL_SEMA_HXX