dynamic_link.h

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/*
    Copyright (c) 2005-2020 Intel Corporation

    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 __TBB_dynamic_link
#define __TBB_dynamic_link

// Support for dynamic loading entry points from other shared libraries.

#include "tbb/tbb_stddef.h"

#ifdef LIBRARY_ASSERT
    #undef __TBB_ASSERT
    #define __TBB_ASSERT(x,y) LIBRARY_ASSERT(x,y)
#else
    #define LIBRARY_ASSERT(x,y) __TBB_ASSERT_EX(x,y)
#endif /* !LIBRARY_ASSERT */

#ifndef OPEN_INTERNAL_NAMESPACE
#define OPEN_INTERNAL_NAMESPACE namespace tbb { namespace internal {
#define CLOSE_INTERNAL_NAMESPACE }}
#endif /* OPEN_INTERNAL_NAMESPACE */

#include <stddef.h>
#if _WIN32
#include "tbb/machine/windows_api.h"
#endif /* _WIN32 */

OPEN_INTERNAL_NAMESPACE

typedef void (*pointer_to_handler)();

// Double cast through the void* in DLD macro is necessary to
// prevent warnings from some compilers (g++ 4.1)
#if __TBB_WEAK_SYMBOLS_PRESENT
#define DLD(s,h) {#s, (pointer_to_handler*)(void*)(&h), (pointer_to_handler)&s}
#define DLD_NOWEAK(s,h) {#s, (pointer_to_handler*)(void*)(&h), NULL}
#else
#define DLD(s,h) {#s, (pointer_to_handler*)(void*)(&h)}
#define DLD_NOWEAK(s,h) DLD(s,h)
#endif /* __TBB_WEAK_SYMBOLS_PRESENT */
struct dynamic_link_descriptor {
    const char* name;
    pointer_to_handler* handler;
#if __TBB_WEAK_SYMBOLS_PRESENT
    pointer_to_handler ptr;
#endif
};

#if _WIN32
typedef HMODULE dynamic_link_handle;
#else
typedef void* dynamic_link_handle;
#endif /* _WIN32 */

const int DYNAMIC_LINK_GLOBAL = 0x01;
const int DYNAMIC_LINK_LOAD   = 0x02;
const int DYNAMIC_LINK_WEAK   = 0x04;
const int DYNAMIC_LINK_ALL    = DYNAMIC_LINK_GLOBAL | DYNAMIC_LINK_LOAD | DYNAMIC_LINK_WEAK;


bool dynamic_link( const char* library,
                   const dynamic_link_descriptor descriptors[],
                   size_t required,
                   dynamic_link_handle* handle = 0,
                   int flags = DYNAMIC_LINK_ALL );

void dynamic_unlink( dynamic_link_handle handle );

void dynamic_unlink_all();

enum dynamic_link_error_t {
    dl_success = 0,
    dl_lib_not_found,     // char const * lib, dlerr_t err
    dl_sym_not_found,     // char const * sym, dlerr_t err
                          // Note: dlerr_t depends on OS: it is char const * on Linux* and macOS*, int on Windows*.
    dl_sys_fail,          // char const * func, int err
    dl_buff_too_small     // none
}; // dynamic_link_error_t

CLOSE_INTERNAL_NAMESPACE

#endif /* __TBB_dynamic_link */