IexNamespace.h 4.3 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_IEXNAMESPACE_H
  35. #define INCLUDED_IEXNAMESPACE_H
  36. //
  37. // The purpose of this file is to make it possible to specify an
  38. // IEX_INTERNAL_NAMESPACE as a preprocessor definition and have all of the
  39. // Iex symbols defined within that namespace rather than the standard
  40. // Iex namespace. Those symbols are made available to client code through
  41. // the IEX_NAMESPACE in addition to the IEX_INTERNAL_NAMESPACE.
  42. //
  43. // To ensure source code compatibility, the IEX_NAMESPACE defaults to Iex
  44. // and then "using namespace IEX_INTERNAL_NAMESPACE;" brings all of the
  45. // declarations from the IEX_INTERNAL_NAMESPACE into the IEX_NAMESPACE. This
  46. // means that client code can continue to use syntax like Iex::BaseExc, but
  47. // at link time it will resolve to a mangled symbol based on the
  48. // IEX_INTERNAL_NAMESPACE.
  49. //
  50. // As an example, if one needed to build against a newer version of Iex and
  51. // have it run alongside an older version in the same application, it is now
  52. // possible to use an internal namespace to prevent collisions between the
  53. // older versions of Iex symbols and the newer ones. To do this, the
  54. // following could be defined at build time:
  55. //
  56. // IEX_INTERNAL_NAMESPACE = Iex_v2
  57. //
  58. // This means that declarations inside Iex headers look like this (after the
  59. // preprocessor has done its work):
  60. //
  61. // namespace Iex_v2 {
  62. // ...
  63. // class declarations
  64. // ...
  65. // }
  66. //
  67. // namespace Iex {
  68. // using namespace Iex_v2;
  69. // }
  70. //
  71. //
  72. // Open Source version of this file pulls in the IlmBaseConfig.h file
  73. // for the configure time options.
  74. //
  75. #include "IlmBaseConfig.h"
  76. #ifndef IEX_NAMESPACE
  77. #define IEX_NAMESPACE Iex
  78. #endif
  79. #ifndef IEX_INTERNAL_NAMESPACE
  80. #define IEX_INTERNAL_NAMESPACE IEX_NAMESPACE
  81. #endif
  82. //
  83. // We need to be sure that we import the internal namespace into the public one.
  84. // To do this, we use the small bit of code below which initially defines
  85. // IEX_INTERNAL_NAMESPACE (so it can be referenced) and then defines
  86. // IEX_NAMESPACE and pulls the internal symbols into the public namespace.
  87. //
  88. namespace IEX_INTERNAL_NAMESPACE {}
  89. namespace IEX_NAMESPACE {
  90. using namespace IEX_INTERNAL_NAMESPACE;
  91. }
  92. //
  93. // There are identical pairs of HEADER/SOURCE ENTER/EXIT macros so that
  94. // future extension to the namespace mechanism is possible without changing
  95. // project source code.
  96. //
  97. #define IEX_INTERNAL_NAMESPACE_HEADER_ENTER namespace IEX_INTERNAL_NAMESPACE {
  98. #define IEX_INTERNAL_NAMESPACE_HEADER_EXIT }
  99. #define IEX_INTERNAL_NAMESPACE_SOURCE_ENTER namespace IEX_INTERNAL_NAMESPACE {
  100. #define IEX_INTERNAL_NAMESPACE_SOURCE_EXIT }
  101. #endif // INCLUDED_IEXNAMESPACE_H