folly/folly/memory/detail/MallocImpl.cpp

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * 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.
 */

#include <folly/memory/detail/MallocImpl.h>

extern "C" {

#ifdef _MSC_VER
// MSVC doesn't have weak symbols, so do some linker magic
// to emulate them. (the magic is in the header)
const char* mallocxWeak = nullptr;
const char* rallocxWeak = nullptr;
const char* xallocxWeak = nullptr;
const char* sallocxWeak = nullptr;
const char* dallocxWeak = nullptr;
const char* sdallocxWeak = nullptr;
const char* nallocxWeak = nullptr;
const char* mallctlWeak = nullptr;
const char* mallctlnametomibWeak = nullptr;
const char* mallctlbymibWeak = nullptr;
const char* MallocExtension_Internal_GetNumericPropertyWeak = nullptr;
#elif !FOLLY_HAVE_WEAK_SYMBOLS
#if (!defined(USE_JEMALLOC) && !defined(FOLLY_USE_JEMALLOC)) || FOLLY_SANITIZE
void* (*mallocx)(size_t, int) = …;
void* (*rallocx)(void*, size_t, int) = …;
size_t (*xallocx)(void*, size_t, size_t, int) = …;
size_t (*sallocx)(const void*, int) = …;
void (*dallocx)(void*, int) = …;
void (*sdallocx)(void*, size_t, int) = …;
size_t (*nallocx)(size_t, int) = …;
int (*mallctl)(const char*, void*, size_t*, void*, size_t) = …;
int (*mallctlnametomib)(const char*, size_t*, size_t*) = …;
int (*mallctlbymib)(const size_t*, size_t, void*, size_t*, void*, size_t) = …;
#endif
bool (*MallocExtension_Internal_GetNumericProperty)(
    const char*, size_t, size_t*) = …;
#endif
}