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Diffstat (limited to 'src/gav1/symbol_visibility.h')
| -rw-r--r-- | src/gav1/symbol_visibility.h | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/src/gav1/symbol_visibility.h b/src/gav1/symbol_visibility.h new file mode 100644 index 0000000..ad7498c --- /dev/null +++ b/src/gav1/symbol_visibility.h @@ -0,0 +1,88 @@ +/* + * Copyright 2019 The libgav1 Authors + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef LIBGAV1_SRC_GAV1_SYMBOL_VISIBILITY_H_ +#define LIBGAV1_SRC_GAV1_SYMBOL_VISIBILITY_H_ + +// This module defines the LIBGAV1_PUBLIC macro. LIBGAV1_PUBLIC, when combined +// with the flags -fvisibility=hidden and -fvisibility-inlines-hidden, restricts +// symbol availability when users use the shared object form of libgav1. The +// intent is to prevent exposure of libgav1 internals to users of the library, +// and to avoid ABI compatibility problems that changes to libgav1 internals +// would cause for users of the libgav1 shared object. +// +// Examples: +// +// This form makes a class and all of its members part of the public API: +// +// class LIBGAV1_PUBLIC A { +// public: +// A(); +// ~A(); +// void Foo(); +// int Bar(); +// }; +// +// A::A(), A::~A(), A::Foo(), and A::Bar() are all available to code linking to +// the shared object when this form is used. +// +// This form exposes a single class method as part of the public API: +// +// class B { +// public: +// B(); +// ~B(); +// LIBGAV1_PUBLIC int Foo(); +// }; +// +// In this examples only B::Foo() is available to the user of the shared object. +// +// Non-class member functions can also be exposed individually: +// +// LIBGAV1_PUBLIC void Bar(); +// +// In this example Bar() would be available to users of the shared object. +// +// Much of the above information and more can be found at +// https://gcc.gnu.org/wiki/Visibility + +#if !defined(LIBGAV1_PUBLIC) +#if defined(_WIN32) +#if defined(LIBGAV1_BUILDING_DLL) && LIBGAV1_BUILDING_DLL +#if defined(__GNUC__) +#define LIBGAV1_PUBLIC __attribute__((dllexport)) +#else +#define LIBGAV1_PUBLIC __declspec(dllexport) +#endif // defined(__GNUC__) +#elif defined(LIBGAV1_BUILDING_DLL) +#ifdef __GNUC__ +#define LIBGAV1_PUBLIC __attribute__((dllimport)) +#else +#define LIBGAV1_PUBLIC __declspec(dllimport) +#endif // defined(__GNUC__) +#else +#define LIBGAV1_PUBLIC +#endif // defined(LIBGAV1_BUILDING_DLL) && LIBGAV1_BUILDING_DLL +#else +#if defined(__GNUC__) && __GNUC__ >= 4 +#define LIBGAV1_PUBLIC __attribute__((visibility("default"))) +#else +#define LIBGAV1_PUBLIC +#endif +#endif // defined(_WIN32) +#endif // defined(LIBGAV1_PUBLIC) + +#endif // LIBGAV1_SRC_GAV1_SYMBOL_VISIBILITY_H_ |