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- //
- // SPDX-License-Identifier: BSD-3-Clause
- // Copyright (c) Contributors to the OpenEXR Project.
- //
- #ifndef INCLUDED_IMFNAMESPACE_H
- #define INCLUDED_IMFNAMESPACE_H
- //
- // The purpose of this file is to have all of the Imath symbols defined within
- // the OPENEXR_IMF_INTERNAL_NAMESPACE namespace rather than the standard Imath
- // namespace. Those symbols are made available to client code through the
- // OPENEXR_IMF_NAMESPACE in addition to the OPENEXR_IMF_INTERNAL_NAMESPACE.
- //
- // To ensure source code compatibility, the OPENEXR_IMF_NAMESPACE defaults to
- // Imath and then "using namespace OPENEXR_IMF_INTERNAL_NAMESPACE;" brings all
- // of the declarations from the OPENEXR_IMF_INTERNAL_NAMESPACE into the
- // OPENEXR_IMF_NAMESPACE.
- // This means that client code can continue to use syntax like
- // Imf::Header, but at link time it will resolve to a
- // mangled symbol based on the OPENEXR_IMF_INTERNAL_NAMESPACE.
- //
- // As an example, if one needed to build against a newer version of Imath and
- // have it run alongside an older version in the same application, it is now
- // possible to use an internal namespace to prevent collisions between the
- // older versions of Imath symbols and the newer ones. To do this, the
- // following could be defined at build time:
- //
- // OPENEXR_IMF_INTERNAL_NAMESPACE = Imf_v2
- //
- // This means that declarations inside Imath headers look like this (after
- // the preprocessor has done its work):
- //
- // namespace Imf_v2 {
- // ...
- // class declarations
- // ...
- // }
- //
- // namespace Imf {
- // using namespace IMF_NAMESPACE_v2;
- // }
- //
- //
- // Open Source version of this file pulls in the OpenEXRConfig.h file
- // for the configure time options.
- //
- #include "OpenEXRConfig.h"
- #ifndef OPENEXR_IMF_NAMESPACE
- #define OPENEXR_IMF_NAMESPACE Imf
- #endif
- #ifndef OPENEXR_IMF_INTERNAL_NAMESPACE
- #define OPENEXR_IMF_INTERNAL_NAMESPACE OPENEXR_IMF_NAMESPACE
- #endif
- //
- // We need to be sure that we import the internal namespace into the public one.
- // To do this, we use the small bit of code below which initially defines
- // OPENEXR_IMF_INTERNAL_NAMESPACE (so it can be referenced) and then defines
- // OPENEXR_IMF_NAMESPACE and pulls the internal symbols into the public
- // namespace.
- //
- namespace OPENEXR_IMF_INTERNAL_NAMESPACE {}
- namespace OPENEXR_IMF_NAMESPACE {
- using namespace OPENEXR_IMF_INTERNAL_NAMESPACE;
- }
- //
- // There are identical pairs of HEADER/SOURCE ENTER/EXIT macros so that
- // future extension to the namespace mechanism is possible without changing
- // project source code.
- //
- #define OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER namespace OPENEXR_IMF_INTERNAL_NAMESPACE {
- #define OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT }
- #define OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_ENTER namespace OPENEXR_IMF_INTERNAL_NAMESPACE {
- #define OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT }
- #endif /* INCLUDED_IMFNAMESPACE_H */
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