IlmThreadNamespace.h 4.5 KB

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  1. ///////////////////////////////////////////////////////////////////////////
  2. //
  3. // Copyright (c) 2012, 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:
  11. // * Redistributions of source code must retain the above copyright
  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
  23. // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24. // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25. // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26. // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27. // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28. // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29. // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30. // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31. // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32. //
  33. ///////////////////////////////////////////////////////////////////////////
  34. #ifndef INCLUDED_ILMTHREADNAMESPACE_H
  35. #define INCLUDED_ILMTHREADNAMESPACE_H
  36. //
  37. // The purpose of this file is to make it possible to specify an
  38. // ILMTHREAD_INTERNAL_NAMESPACE as a preprocessor definition and have all of
  39. // the IlmThread symbols defined within that namespace rather than the
  40. // standard IlmThread namespace. Those symbols are made available to client
  41. // code through the ILMTHREAD_NAMESPACE in addition to the
  42. // ILMTHREAD_INTERNAL_NAMESPACE.
  43. //
  44. // To ensure source code compatibility, the ILMTHREAD_NAMESPACE defaults to
  45. // IlmThread and then "using namespace ILMTHREAD_INTERNAL_NAMESPACE;" brings
  46. // all of the declarations from the ILMTHREAD_INTERNAL_NAMESPACE into the
  47. // ILMTHREAD_NAMESPACE. This means that client code can continue to use
  48. // syntax like IlmThread::Thread, but at link time it will resolve to a
  49. // mangled symbol based on the ILMTHREAD_INTERNAL_NAMESPACE.
  50. //
  51. // As an example, if one needed to build against a newer version of IlmThread
  52. // and have it run alongside an older version in the same application, it is
  53. // now possible to use an internal namespace to prevent collisions between
  54. // the older versions of IlmThread symbols and the newer ones. To do this,
  55. // the following could be defined at build time:
  56. //
  57. // ILMTHREAD_INTERNAL_NAMESPACE = IlmThread_v2
  58. //
  59. // This means that declarations inside IlmThread headers look like this
  60. // (after the preprocessor has done its work):
  61. //
  62. // namespace IlmThread_v2 {
  63. // ...
  64. // class declarations
  65. // ...
  66. // }
  67. //
  68. // namespace IlmThread {
  69. // using namespace IlmThread_v2;
  70. // }
  71. //
  72. //
  73. // Open Source version of this file pulls in the IlmBaseConfig.h file
  74. // for the configure time options.
  75. //
  76. #include "IlmBaseConfig.h"
  77. #ifndef ILMTHREAD_NAMESPACE
  78. #define ILMTHREAD_NAMESPACE IlmThread
  79. #endif
  80. #ifndef ILMTHREAD_INTERNAL_NAMESPACE
  81. #define ILMTHREAD_INTERNAL_NAMESPACE ILMTHREAD_NAMESPACE
  82. #endif
  83. //
  84. // We need to be sure that we import the internal namespace into the public one.
  85. // To do this, we use the small bit of code below which initially defines
  86. // ILMTHREAD_INTERNAL_NAMESPACE (so it can be referenced) and then defines
  87. // ILMTHREAD_NAMESPACE and pulls the internal symbols into the public
  88. // namespace.
  89. //
  90. namespace ILMTHREAD_INTERNAL_NAMESPACE {}
  91. namespace ILMTHREAD_NAMESPACE {
  92. using namespace ILMTHREAD_INTERNAL_NAMESPACE;
  93. }
  94. //
  95. // There are identical pairs of HEADER/SOURCE ENTER/EXIT macros so that
  96. // future extension to the namespace mechanism is possible without changing
  97. // project source code.
  98. //
  99. #define ILMTHREAD_INTERNAL_NAMESPACE_HEADER_ENTER namespace ILMTHREAD_INTERNAL_NAMESPACE {
  100. #define ILMTHREAD_INTERNAL_NAMESPACE_HEADER_EXIT }
  101. #define ILMTHREAD_INTERNAL_NAMESPACE_SOURCE_ENTER namespace ILMTHREAD_INTERNAL_NAMESPACE {
  102. #define ILMTHREAD_INTERNAL_NAMESPACE_SOURCE_EXIT }
  103. #endif // INCLUDED_ILMTHREADNAMESPACE_H