1 ///////////////////////////////////////////////////////////////////////////
2 //
3 // Copyright (c) 2005, Industrial Light & Magic, a division of Lucas
4 // Digital Ltd. LLC
5 //
6 // All rights reserved.
7 //
8 // Redistribution and use in source and binary forms, with or without
9 // modification, are permitted provided that the following conditions are
10 // met:
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12 // notice, this list of conditions and the following disclaimer.
13 // * Redistributions in binary form must reproduce the above
14 // copyright notice, this list of conditions and the following disclaimer
15 // in the documentation and/or other materials provided with the
16 // distribution.
17 // * Neither the name of Industrial Light & Magic nor the names of
18 // its contributors may be used to endorse or promote products derived
19 // from this software without specific prior written permission.
20 //
21 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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31 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 //
33 ///////////////////////////////////////////////////////////////////////////
34
35 //-----------------------------------------------------------------------------
36 //
37 // class Semaphore -- implementation for platforms
38 // that support Posix threads and Posix semaphores
39 //
40 //-----------------------------------------------------------------------------
41
42 #include "IlmBaseConfig.h"
43
44 #if HAVE_PTHREAD && HAVE_POSIX_SEMAPHORES
45
46 #include "IlmThreadSemaphore.h"
47 #include "Iex.h"
48 #include <assert.h>
49
50 namespace IlmThread {
51
52
Semaphore(unsigned int value)53 Semaphore::Semaphore (unsigned int value)
54 {
55 if (::sem_init (&_semaphore, 0, value))
56 Iex::throwErrnoExc ("Cannot initialize semaphore (%T).");
57 }
58
59
~Semaphore()60 Semaphore::~Semaphore ()
61 {
62 int error = ::sem_destroy (&_semaphore);
63 assert (error == 0);
64 }
65
66
67 void
wait()68 Semaphore::wait ()
69 {
70 ::sem_wait (&_semaphore);
71 }
72
73
74 bool
tryWait()75 Semaphore::tryWait ()
76 {
77 return sem_trywait (&_semaphore) == 0;
78 }
79
80
81 void
post()82 Semaphore::post ()
83 {
84 if (::sem_post (&_semaphore))
85 Iex::throwErrnoExc ("Post operation on semaphore failed (%T).");
86 }
87
88
89 int
value() const90 Semaphore::value () const
91 {
92 int value;
93
94 if (::sem_getvalue (&_semaphore, &value))
95 Iex::throwErrnoExc ("Cannot read semaphore value (%T).");
96
97 return value;
98 }
99
100
101 } // namespace IlmThread
102
103 #endif
104