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- // Copyright 2014 Renato Tegon Forti, Antony Polukhin.
- // Copyright Antony Polukhin, 2015-2025.
- //
- // Distributed under the Boost Software License, Version 1.0.
- // (See accompanying file LICENSE_1_0.txt
- // or copy at http://www.boost.org/LICENSE_1_0.txt)
- #ifndef BOOST_DLL_IMPORT_HPP
- #define BOOST_DLL_IMPORT_HPP
- #include <boost/dll/config.hpp>
- #include <boost/dll/shared_library.hpp>
- #include <memory> // std::addressof
- #include <type_traits>
- #ifdef BOOST_HAS_PRAGMA_ONCE
- # pragma once
- #endif
- /// \file boost/dll/import.hpp
- /// \brief Contains all the boost::dll::import* reference counting
- /// functions that hold a shared pointer to the instance of
- /// boost::dll::shared_library.
- namespace boost { namespace dll {
- namespace detail {
- template <class T>
- class library_function {
- // Copying of `boost::dll::shared_library` is very expensive, so we use a `shared_ptr` to make it faster.
- boost::dll::detail::shared_ptr<T> f_;
- public:
- inline library_function(const boost::dll::detail::shared_ptr<shared_library>& lib, T* func_ptr) noexcept
- : f_(lib, func_ptr)
- {}
- // Compilation error at this point means that imported function
- // was called with unmatching parameters.
- //
- // Example:
- // auto f = dll::import_symbol<void(int)>("function", "lib.so");
- // f("Hello"); // error: invalid conversion from 'const char*' to 'int'
- // f(1, 2); // error: too many arguments to function
- // f(); // error: too few arguments to function
- template <class... Args>
- inline auto operator()(Args&&... args) const
- -> decltype( (*f_)(static_cast<Args&&>(args)...) )
- {
- return (*f_)(static_cast<Args&&>(args)...);
- }
- };
- template <class T>
- using import_type = typename std::conditional<
- std::is_object<T>::value,
- boost::dll::detail::shared_ptr<T>,
- boost::dll::detail::library_function<T>
- >::type;
- } // namespace detail
- #ifndef BOOST_DLL_DOXYGEN
- # define BOOST_DLL_IMPORT_RESULT_TYPE inline boost::dll::detail::import_type<T>
- #endif
- /*!
- * Returns callable object or std::shared_ptr<T> (boost::shared_ptr<T> if
- * BOOST_DLL_USE_BOOST_SHARED_PTR is defined) that holds the symbol imported
- * from the loaded library. Returned value refcounts usage
- * of the loaded shared library, so that it won't get unload until all copies of return value
- * are not destroyed.
- *
- * This call will succeed if call to \forcedlink{shared_library}`::has(const char* )`
- * function with the same symbol name returned `true`.
- *
- * For importing symbols by \b alias names use \forcedlink{import_alias} method.
- *
- * \b Examples:
- *
- * \code
- * std::function<int(int)> f = import_symbol<int(int)>("test_lib.so", "integer_func_name");
- *
- * auto f_cpp11 = import_symbol<int(int)>("test_lib.so", "integer_func_name");
- * \endcode
- *
- * \code
- * std::shared_ptr<int> i = import_symbol<int>("test_lib.so", "integer_name");
- * \endcode
- *
- * \b Template \b parameter \b T: Type of the symbol that we are going to import. Must be explicitly specified.
- *
- * \param lib Path to shared library or shared library to load function from.
- * \param name Null-terminated C or C++ mangled name of the function to import. Can handle std::string, char*, const char*.
- * \param mode An mode that will be used on library load.
- *
- * \return callable object if T is a function type, or std::shared_ptr<T> (boost::shared_ptr<T> if
- * BOOST_DLL_USE_BOOST_SHARED_PTR is defined) if T is an object type.
- *
- * \throw \forcedlinkfs{system_error} if symbol does not exist or if the DLL/DSO was not loaded.
- * Overload that accepts path also throws std::bad_alloc in case of insufficient memory.
- */
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_symbol(const boost::dll::fs::path& lib, const char* name,
- load_mode::type mode = load_mode::default_mode)
- {
- using type = boost::dll::detail::import_type<T>;
- auto p = boost::dll::detail::make_shared<boost::dll::shared_library>(lib, mode);
- auto* addr = std::addressof(p->get<T>(name));
- return type(std::move(p), addr);
- }
- //! \overload boost::dll::import_symbol(const boost::dll::fs::path& lib, const char* name, load_mode::type mode)
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_symbol(const boost::dll::fs::path& lib, const std::string& name,
- load_mode::type mode = load_mode::default_mode)
- {
- return dll::import_symbol<T>(lib, name.c_str(), mode);
- }
- //! \overload boost::dll::import_symbol(const boost::dll::fs::path& lib, const char* name, load_mode::type mode)
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_symbol(const shared_library& lib, const char* name) {
- using type = boost::dll::detail::import_type<T>;
- auto p = boost::dll::detail::make_shared<boost::dll::shared_library>(lib);
- return type(p, std::addressof(p->get<T>(name)));
- }
- //! \overload boost::dll::import_symbol(const boost::dll::fs::path& lib, const char* name, load_mode::type mode)
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_symbol(const shared_library& lib, const std::string& name) {
- return dll::import_symbol<T>(lib, name.c_str());
- }
- //! \overload boost::dll::import_symbol(const boost::dll::fs::path& lib, const char* name, load_mode::type mode)
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_symbol(shared_library&& lib, const char* name) {
- using type = boost::dll::detail::import_type<T>;
- auto p = boost::dll::detail::make_shared<boost::dll::shared_library>(
- std::move(lib)
- );
- auto* addr = std::addressof(p->get<T>(name));
- return type(std::move(p), addr);
- }
- //! \overload boost::dll::import_symbol(const boost::dll::fs::path& lib, const char* name, load_mode::type mode)
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_symbol(shared_library&& lib, const std::string& name) {
- return dll::import_symbol<T>(std::move(lib), name.c_str());
- }
- /*!
- * Returns callable object or std::shared_ptr<T> (boost::shared_ptr<T> if
- * BOOST_DLL_USE_BOOST_SHARED_PTR is defined) that holds the symbol imported
- * from the loaded library. Returned value refcounts usage
- * of the loaded shared library, so that it won't get unload until all copies of return value
- * are not destroyed.
- *
- * This call will succeed if call to \forcedlink{shared_library}`::has(const char* )`
- * function with the same symbol name returned `true`.
- *
- * For importing symbols by \b non \b alias names use \forcedlink{import} method.
- *
- * \b Examples:
- *
- * \code
- * std::function<int(int)> f = import_alias<int(int)>("test_lib.so", "integer_func_alias_name");
- *
- * auto f_cpp11 = import_alias<int(int)>("test_lib.so", "integer_func_alias_name");
- * \endcode
- *
- * \code
- * std::shared_ptr<int> i = import_alias<int>("test_lib.so", "integer_alias_name");
- * \endcode
- *
- * \code
- * \endcode
- *
- * \b Template \b parameter \b T: Type of the symbol alias that we are going to import. Must be explicitly specified.
- *
- * \param lib Path to shared library or shared library to load function from.
- * \param name Null-terminated C or C++ mangled name of the function or variable to import. Can handle std::string, char*, const char*.
- * \param mode An mode that will be used on library load.
- *
- * \return callable object if T is a function type, or std::shared_ptr<T> (boost::shared_ptr<T> if
- * BOOST_DLL_USE_BOOST_SHARED_PTR is defined) if T is an object type.
- *
- * \throw \forcedlinkfs{system_error} if symbol does not exist or if the DLL/DSO was not loaded.
- * Overload that accepts path also throws std::bad_alloc in case of insufficient memory.
- */
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_alias(const boost::dll::fs::path& lib, const char* name,
- load_mode::type mode = load_mode::default_mode)
- {
- using type = boost::dll::detail::import_type<T>;
- auto p = boost::dll::detail::make_shared<boost::dll::shared_library>(lib, mode);
- auto* addr = p->get<T*>(name);
- return type(std::move(p), addr);
- }
- //! \overload boost::dll::import_alias(const boost::dll::fs::path& lib, const char* name, load_mode::type mode)
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_alias(const boost::dll::fs::path& lib, const std::string& name,
- load_mode::type mode = load_mode::default_mode)
- {
- return dll::import_alias<T>(lib, name.c_str(), mode);
- }
- //! \overload boost::dll::import_alias(const boost::dll::fs::path& lib, const char* name, load_mode::type mode)
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_alias(const shared_library& lib, const char* name) {
- using type = boost::dll::detail::import_type<T>;
- auto p = boost::dll::detail::make_shared<boost::dll::shared_library>(lib);
- auto* addr = p->get<T*>(name);
- return type(std::move(p), addr);
- }
- //! \overload boost::dll::import_alias(const boost::dll::fs::path& lib, const char* name, load_mode::type mode)
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_alias(const shared_library& lib, const std::string& name) {
- return dll::import_alias<T>(lib, name.c_str());
- }
- //! \overload boost::dll::import_alias(const boost::dll::fs::path& lib, const char* name, load_mode::type mode)
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_alias(shared_library&& lib, const char* name) {
- using type = boost::dll::detail::import_type<T>;
- auto p = boost::dll::detail::make_shared<boost::dll::shared_library>(
- std::move(lib)
- );
- auto* addr = p->get<T*>(name);
- return type(std::move(p), addr);
- }
- //! \overload boost::dll::import_alias(const boost::dll::fs::path& lib, const char* name, load_mode::type mode)
- template <class T>
- BOOST_DLL_IMPORT_RESULT_TYPE import_alias(shared_library&& lib, const std::string& name) {
- return dll::import_alias<T>(std::move(lib), name.c_str());
- }
- #undef BOOST_DLL_IMPORT_RESULT_TYPE
- }} // boost::dll
- #endif // BOOST_DLL_IMPORT_HPP
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