// Copyright 2014 Renato Tegon Forti, Antony Polukhin.
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// Copyright 2015-2019 Antony Polukhin.
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt
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// or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_DLL_SHARED_LIBRARY_HPP
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#define BOOST_DLL_SHARED_LIBRARY_HPP
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/// \file boost/dll/shared_library.hpp
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/// \brief Contains the boost::dll::shared_library class, core class for all the
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/// DLL/DSO operations.
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#include <boost/dll/config.hpp>
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#include <boost/predef/os.h>
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#include <boost/core/enable_if.hpp>
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#include <boost/core/explicit_operator_bool.hpp>
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#include <boost/type_traits/is_member_pointer.hpp>
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#include <boost/dll/detail/system_error.hpp>
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#include <boost/dll/detail/aggressive_ptr_cast.hpp>
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#if BOOST_OS_WINDOWS
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# include <boost/dll/detail/windows/shared_library_impl.hpp>
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#else
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# include <boost/dll/detail/posix/shared_library_impl.hpp>
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#endif
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#ifdef BOOST_HAS_PRAGMA_ONCE
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# pragma once
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#endif
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namespace boost { namespace dll {
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/*!
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* \brief This class can be used to load a
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* Dynamic link libraries (DLL's) or Shared Libraries, also know
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* as dynamic shared objects (DSO's) and get their exported
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* symbols (functions and variables).
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*
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* shared_library instances share reference count to an actual loaded DLL/DSO, so it
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* is safe and memory efficient to have multiple instances of shared_library referencing the same DLL/DSO
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* even if those instances were loaded using different paths (relative + absolute) referencing the same object.
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*
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* On Linux/POSIX link with library "dl". "-fvisibility=hidden" flag is also recommended for use on Linux/POSIX.
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*/
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class shared_library
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/// @cond
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: private boost::dll::detail::shared_library_impl
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/// @endcond
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{
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typedef boost::dll::detail::shared_library_impl base_t;
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BOOST_COPYABLE_AND_MOVABLE(shared_library)
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public:
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#ifdef BOOST_DLL_DOXYGEN
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typedef platform_specific native_handle_t;
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#else
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typedef shared_library_impl::native_handle_t native_handle_t;
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#endif
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/*!
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* Creates in anstance that does not reference any DLL/DSO.
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*
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* \post this->is_loaded() returns false.
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* \throw Nothing.
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*/
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shared_library() BOOST_NOEXCEPT {}
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/*!
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* Copy constructor that increments the reference count of an underlying shared library.
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* Same as calling constructor with `lib.location()` parameter.
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*
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* \param lib A library to copy.
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* \post lib == *this
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* \throw \forcedlinkfs{system_error}, std::bad_alloc in case of insufficient memory.
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*/
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shared_library(const shared_library& lib)
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: base_t()
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{
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assign(lib);
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}
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/*!
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* Copy constructor that increments the reference count of an underlying shared library.
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* Same as calling constructor with `lib.location(), ec` parameters.
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*
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* \param lib A shared library to copy.
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* \param ec Variable that will be set to the result of the operation.
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* \post lib == *this
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* \throw std::bad_alloc in case of insufficient memory.
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*/
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shared_library(const shared_library& lib, boost::dll::fs::error_code& ec)
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: base_t()
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{
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assign(lib, ec);
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}
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/*!
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* Move constructor. Does not invalidate existing symbols and functions loaded from lib.
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*
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* \param lib A shared library to move from.
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* \post lib.is_loaded() returns false, this->is_loaded() return true.
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* \throw Nothing.
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*/
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shared_library(BOOST_RV_REF(shared_library) lib) BOOST_NOEXCEPT
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: base_t(boost::move(static_cast<base_t&>(lib)))
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{}
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/*!
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* Loads a library by specified path with a specified mode.
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*
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* \param lib_path Library file name. Can handle std::string, const char*, std::wstring,
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* const wchar_t* or \forcedlinkfs{path}.
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* \param mode A mode that will be used on library load.
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* \throw \forcedlinkfs{system_error}, std::bad_alloc in case of insufficient memory.
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*/
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explicit shared_library(const boost::dll::fs::path& lib_path, load_mode::type mode = load_mode::default_mode) {
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shared_library::load(lib_path, mode);
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}
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/*!
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* Loads a library by specified path with a specified mode.
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*
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* \param lib_path Library file name. Can handle std::string, const char*, std::wstring,
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* const wchar_t* or \forcedlinkfs{path}.
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* \param mode A mode that will be used on library load.
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* \param ec Variable that will be set to the result of the operation.
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* \throw std::bad_alloc in case of insufficient memory.
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*/
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shared_library(const boost::dll::fs::path& lib_path, boost::dll::fs::error_code& ec, load_mode::type mode = load_mode::default_mode) {
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shared_library::load(lib_path, mode, ec);
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}
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//! \overload shared_library(const boost::dll::fs::path& lib_path, boost::dll::fs::error_code& ec, load_mode::type mode = load_mode::default_mode)
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shared_library(const boost::dll::fs::path& lib_path, load_mode::type mode, boost::dll::fs::error_code& ec) {
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shared_library::load(lib_path, mode, ec);
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}
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/*!
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* Assignment operator. If this->is_loaded() then calls this->unload(). Does not invalidate existing symbols and functions loaded from lib.
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*
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* \param lib A shared library to assign from.
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* \post lib == *this
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* \throw \forcedlinkfs{system_error}, std::bad_alloc in case of insufficient memory.
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*/
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shared_library& operator=(BOOST_COPY_ASSIGN_REF(shared_library) lib) {
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boost::dll::fs::error_code ec;
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assign(lib, ec);
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if (ec) {
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boost::dll::detail::report_error(ec, "boost::dll::shared_library::operator= failed");
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}
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return *this;
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}
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/*!
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* Move assignment operator. If this->is_loaded() then calls this->unload(). Does not invalidate existing symbols and functions loaded from lib.
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*
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* \param lib A library to move from.
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* \post lib.is_loaded() returns false.
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* \throw Nothing.
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*/
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shared_library& operator=(BOOST_RV_REF(shared_library) lib) BOOST_NOEXCEPT {
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if (lib.native() != native()) {
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swap(lib);
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}
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return *this;
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}
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/*!
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* Destroys the object by calling `unload()`. If library was loaded multiple times
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* by different instances, the actual DLL/DSO won't be unloaded until
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* there is at least one instance that references the DLL/DSO.
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*
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* \throw Nothing.
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*/
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~shared_library() BOOST_NOEXCEPT {}
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/*!
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* Makes *this share the same shared object as lib. If *this is loaded, then unloads it.
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*
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* \post lib.location() == this->location(), lib == *this
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* \param lib A library to copy.
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* \param ec Variable that will be set to the result of the operation.
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* \throw std::bad_alloc in case of insufficient memory.
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*/
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shared_library& assign(const shared_library& lib, boost::dll::fs::error_code& ec) {
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ec.clear();
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if (native() == lib.native()) {
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return *this;
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}
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if (!lib) {
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unload();
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return *this;
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}
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boost::dll::fs::path loc = lib.location(ec);
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if (ec) {
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return *this;
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}
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shared_library copy(loc, ec);
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if (ec) {
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return *this;
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}
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swap(copy);
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return *this;
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}
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/*!
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* Makes *this share the same shared object as lib. If *this is loaded, then unloads it.
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*
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* \param lib A library instance to assign from.
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* \post lib.location() == this->location()
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* \throw \forcedlinkfs{system_error}, std::bad_alloc in case of insufficient memory.
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*/
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shared_library& assign(const shared_library& lib) {
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boost::dll::fs::error_code ec;
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assign(lib, ec);
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if (ec) {
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boost::dll::detail::report_error(ec, "boost::dll::shared_library::assign() failed");
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}
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return *this;
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}
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/*!
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* Loads a library by specified path with a specified mode.
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*
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* Note that if some library is already loaded in this instance, load will
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* call unload() and then load the new provided library.
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*
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* \param lib_path Library file name. Can handle std::string, const char*, std::wstring,
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* const wchar_t* or \forcedlinkfs{path}.
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* \param mode A mode that will be used on library load.
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* \throw \forcedlinkfs{system_error}, std::bad_alloc in case of insufficient memory.
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*
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*/
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void load(const boost::dll::fs::path& lib_path, load_mode::type mode = load_mode::default_mode) {
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boost::dll::fs::error_code ec;
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base_t::load(lib_path, mode, ec);
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if (ec) {
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boost::dll::detail::report_error(ec, "boost::dll::shared_library::load() failed");
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}
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}
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/*!
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* Loads a library by specified path with a specified mode.
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*
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* Note that if some library is already loaded in this instance, load will
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* call unload() and then load the new provided library.
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*
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* \param lib_path Library file name. Can handle std::string, const char*, std::wstring,
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* const wchar_t* or \forcedlinkfs{path}.
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* \param ec Variable that will be set to the result of the operation.
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* \param mode A mode that will be used on library load.
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* \throw std::bad_alloc in case of insufficient memory.
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*/
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void load(const boost::dll::fs::path& lib_path, boost::dll::fs::error_code& ec, load_mode::type mode = load_mode::default_mode) {
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ec.clear();
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base_t::load(lib_path, mode, ec);
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}
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//! \overload void load(const boost::dll::fs::path& lib_path, boost::dll::fs::error_code& ec, load_mode::type mode = load_mode::default_mode)
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void load(const boost::dll::fs::path& lib_path, load_mode::type mode, boost::dll::fs::error_code& ec) {
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ec.clear();
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base_t::load(lib_path, mode, ec);
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}
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/*!
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* Unloads a shared library. If library was loaded multiple times
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* by different instances, the actual DLL/DSO won't be unloaded until
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* there is at least one instance that references the DLL/DSO.
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*
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* \post this->is_loaded() returns false.
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* \throw Nothing.
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*/
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void unload() BOOST_NOEXCEPT {
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base_t::unload();
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}
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/*!
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* Check if an library is loaded.
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*
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* \return true if a library has been loaded.
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* \throw Nothing.
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*/
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bool is_loaded() const BOOST_NOEXCEPT {
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return base_t::is_loaded();
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}
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/*!
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* Check if an library is not loaded.
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*
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* \return true if a library has not been loaded.
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* \throw Nothing.
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*/
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bool operator!() const BOOST_NOEXCEPT {
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return !is_loaded();
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}
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/*!
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* Check if an library is loaded.
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*
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* \return true if a library has been loaded.
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* \throw Nothing.
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*/
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BOOST_EXPLICIT_OPERATOR_BOOL()
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/*!
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* Search for a given symbol on loaded library. Works for all symbols, including alias names.
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*
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* \param symbol_name Null-terminated symbol name. Can handle std::string, char*, const char*.
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* \return `true` if the loaded library contains a symbol with a given name.
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* \throw Nothing.
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*/
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bool has(const char* symbol_name) const BOOST_NOEXCEPT {
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boost::dll::fs::error_code ec;
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return is_loaded() && !!base_t::symbol_addr(symbol_name, ec) && !ec;
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}
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//! \overload bool has(const char* symbol_name) const
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bool has(const std::string& symbol_name) const BOOST_NOEXCEPT {
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return has(symbol_name.c_str());
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}
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/*!
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* Returns reference to the symbol (function or variable) with the given name from the loaded library.
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* This call will always succeed and throw nothing if call to `has(const char* )`
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* member function with the same symbol name returned `true`.
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*
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* \b Example:
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* \code
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* int& i0 = lib.get<int>("integer_name");
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* int& i1 = *lib.get<int*>("integer_alias_name");
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* \endcode
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*
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* \tparam T Type of the symbol that we are going to import. Must be explicitly specified.
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* \param symbol_name Null-terminated symbol name. Can handle std::string, char*, const char*.
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* \return Reference to the symbol.
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* \throw \forcedlinkfs{system_error} if symbol does not exist or if the DLL/DSO was not loaded.
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*/
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template <typename T>
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inline typename boost::enable_if_c<boost::is_member_pointer<T>::value || boost::is_reference<T>::value, T>::type get(const std::string& symbol_name) const {
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return get<T>(symbol_name.c_str());
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}
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//! \overload T& get(const std::string& symbol_name) const
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template <typename T>
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inline typename boost::disable_if_c<boost::is_member_pointer<T>::value || boost::is_reference<T>::value, T&>::type get(const std::string& symbol_name) const {
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return get<T>(symbol_name.c_str());
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}
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//! \overload T& get(const std::string& symbol_name) const
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template <typename T>
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inline typename boost::enable_if_c<boost::is_member_pointer<T>::value || boost::is_reference<T>::value, T>::type get(const char* symbol_name) const {
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return boost::dll::detail::aggressive_ptr_cast<T>(
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get_void(symbol_name)
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);
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}
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//! \overload T& get(const std::string& symbol_name) const
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template <typename T>
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inline typename boost::disable_if_c<boost::is_member_pointer<T>::value || boost::is_reference<T>::value, T&>::type get(const char* symbol_name) const {
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return *boost::dll::detail::aggressive_ptr_cast<T*>(
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get_void(symbol_name)
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);
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}
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/*!
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* Returns a symbol (function or variable) from a shared library by alias name of the symbol.
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*
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* \b Example:
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* \code
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* int& i = lib.get_alias<int>("integer_alias_name");
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* \endcode
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*
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* \tparam T Type of the symbol that we are going to import. Must be explicitly specified..
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* \param alias_name Null-terminated alias symbol name. Can handle std::string, char*, const char*.
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* \throw \forcedlinkfs{system_error} if symbol does not exist or if the DLL/DSO was not loaded.
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*/
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template <typename T>
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inline T& get_alias(const char* alias_name) const {
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return *get<T*>(alias_name);
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}
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//! \overload T& get_alias(const char* alias_name) const
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template <typename T>
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inline T& get_alias(const std::string& alias_name) const {
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return *get<T*>(alias_name.c_str());
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}
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private:
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/// @cond
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// get_void is required to reduce binary size: it does not depend on a template
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// parameter and will be instantiated only once.
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void* get_void(const char* sb) const {
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boost::dll::fs::error_code ec;
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if (!is_loaded()) {
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ec = boost::dll::fs::make_error_code(
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boost::dll::fs::errc::bad_file_descriptor
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);
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// report_error() calls dlsym, do not use it here!
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boost::throw_exception(
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boost::dll::fs::system_error(
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ec, "boost::dll::shared_library::get() failed: no library was loaded"
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)
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);
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}
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void* const ret = base_t::symbol_addr(sb, ec);
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if (ec || !ret) {
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boost::dll::detail::report_error(ec, "boost::dll::shared_library::get() failed");
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}
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return ret;
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}
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/// @endcond
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public:
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/*!
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* Returns the native handler of the loaded library.
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*
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* \return Platform-specific handle.
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*/
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native_handle_t native() const BOOST_NOEXCEPT {
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return base_t::native();
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}
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/*!
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* Returns full path and name of this shared object.
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*
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* \b Example:
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* \code
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* shared_library lib("test_lib.dll");
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* filesystem::path full_path = lib.location(); // C:\Windows\System32\test_lib.dll
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* \endcode
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*
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* \return Full path to the shared library.
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* \throw \forcedlinkfs{system_error}, std::bad_alloc.
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*/
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boost::dll::fs::path location() const {
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boost::dll::fs::error_code ec;
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if (!is_loaded()) {
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ec = boost::dll::fs::make_error_code(
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boost::dll::fs::errc::bad_file_descriptor
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);
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boost::throw_exception(
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boost::dll::fs::system_error(
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ec, "boost::dll::shared_library::location() failed (no library was loaded)"
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)
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);
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}
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boost::dll::fs::path full_path = base_t::full_module_path(ec);
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if (ec) {
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boost::dll::detail::report_error(ec, "boost::dll::shared_library::location() failed");
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}
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return full_path;
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}
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/*!
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* Returns full path and name of shared module.
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*
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* \b Example:
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* \code
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* shared_library lib("test_lib.dll");
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* filesystem::path full_path = lib.location(); // C:\Windows\System32\test_lib.dll
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* \endcode
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*
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* \param ec Variable that will be set to the result of the operation.
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* \return Full path to the shared library.
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* \throw std::bad_alloc.
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*/
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boost::dll::fs::path location(boost::dll::fs::error_code& ec) const {
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if (!is_loaded()) {
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ec = boost::dll::fs::make_error_code(
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boost::dll::fs::errc::bad_file_descriptor
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);
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return boost::dll::fs::path();
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}
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ec.clear();
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return base_t::full_module_path(ec);
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}
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/*!
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* Returns suffix of shared module:
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* in a call to load() or the constructor/load.
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*
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* \return The suffix od shared module: ".dll" (Windows), ".so" (Unix/Linux/BSD), ".dylib" (MacOS/IOS)
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*/
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static boost::dll::fs::path suffix() {
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return base_t::suffix();
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}
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/*!
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* Returns the decorated path to a shared module name, i.e. with needed prefix/suffix added.
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*
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* \b Recommendations: Use `load` with `load_mode::append_decorations` instead of constructing the decorated path via `decorate()` and loading by it.
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*
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* For instance, for a path like "path/to/boost" it returns :
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* - path/to/libboost.so on posix platforms
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* - path/to/libboost.dylib on OSX
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* - path/to/boost.dll on Windows
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*
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* Method handles both relative and absolute paths.
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*
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* - Windows note: `decorate()` does not prepend "lib" to the decorated path. Use `load` with `load_mode::append_decorations` for MinGW compatibility purpose.
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* - Posix note: if the initial module name is already prepended with lib, only the suffix() is appended to the path
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*
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* \param sl the module name and path to decorate - for instance : /usr/lib/boost
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*
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* \return The decorated unportable path that may not exists in the filesystem or could be wrong due to platform specifics.
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*/
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static boost::dll::fs::path decorate(const boost::dll::fs::path& sl) {
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return base_t::decorate(sl);
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}
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/*!
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* Swaps two libraries. Does not invalidate existing symbols and functions loaded from libraries.
|
*
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* \param rhs Library to swap with.
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* \throw Nothing.
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*/
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void swap(shared_library& rhs) BOOST_NOEXCEPT {
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base_t::swap(rhs);
|
}
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};
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/// Very fast equality check that compares the actual DLL/DSO objects. Throws nothing.
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inline bool operator==(const shared_library& lhs, const shared_library& rhs) BOOST_NOEXCEPT {
|
return lhs.native() == rhs.native();
|
}
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/// Very fast inequality check that compares the actual DLL/DSO objects. Throws nothing.
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inline bool operator!=(const shared_library& lhs, const shared_library& rhs) BOOST_NOEXCEPT {
|
return lhs.native() != rhs.native();
|
}
|
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/// Compare the actual DLL/DSO objects without any guarantee to be stable between runs. Throws nothing.
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inline bool operator<(const shared_library& lhs, const shared_library& rhs) BOOST_NOEXCEPT {
|
return lhs.native() < rhs.native();
|
}
|
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/// Swaps two shared libraries. Does not invalidate symbols and functions loaded from libraries. Throws nothing.
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inline void swap(shared_library& lhs, shared_library& rhs) BOOST_NOEXCEPT {
|
lhs.swap(rhs);
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}
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}} // boost::dll
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#endif // BOOST_DLL_SHARED_LIBRARY_HPP
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