| /* |
| * Copyright 2017 Facebook, Inc. |
| * |
| * 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. |
| */ |
| |
| #pragma once |
| |
| #include <cstdint> |
| |
| #include <folly/portability/PThread.h> |
| #include <folly/portability/SysSyscall.h> |
| #include <folly/portability/Unistd.h> |
| #include <folly/portability/Windows.h> |
| |
| namespace folly { |
| |
| /** |
| * Get a process-specific identifier for the current thread. |
| * |
| * The return value will uniquely identify the thread within the current |
| * process. |
| * |
| * Note that the return value does not necessarily correspond to an operating |
| * system thread ID. The return value is also only unique within the current |
| * process: getCurrentThreadID() may return the same value for two concurrently |
| * running threads in separate processes. |
| * |
| * The thread ID may be reused once the thread it corresponds to has been |
| * joined. |
| */ |
| inline uint64_t getCurrentThreadID() { |
| #if __APPLE__ |
| return uint64_t(pthread_mach_thread_np(pthread_self())); |
| #elif _WIN32 |
| return uint64_t(GetCurrentThreadId()); |
| #else |
| return uint64_t(pthread_self()); |
| #endif |
| } |
| |
| /** |
| * Get the operating-system level thread ID for the current thread. |
| * |
| * The returned value will uniquely identify this thread on the system. |
| * |
| * This makes it more suitable for logging or displaying in user interfaces |
| * than the result of getCurrentThreadID(). |
| * |
| * There are some potential caveats about this API, however: |
| * |
| * - In theory there is no guarantee that application threads map one-to-one to |
| * kernel threads. An application threading implementation could potentially |
| * share one OS thread across multiple application threads, and/or it could |
| * potentially move application threads between different OS threads over |
| * time. However, in practice all of the platforms we currently support have |
| * a one-to-one mapping between userspace threads and operating system |
| * threads. |
| * |
| * - This API may also be slightly slower than getCurrentThreadID() on some |
| * platforms. This API may require a system call, where getCurrentThreadID() |
| * may only need to read thread-local memory. |
| * |
| * On Linux the returned value is a pid_t, and can be used in contexts |
| * requiring a thread pid_t. |
| * |
| * The thread ID may be reused once the thread it corresponds to has been |
| * joined. |
| */ |
| inline uint64_t getOSThreadID() { |
| #if __APPLE__ |
| uint64_t tid; |
| pthread_threadid_np(nullptr, &tid); |
| return tid; |
| #elif _WIN32 |
| return uint64_t(GetCurrentThreadId()); |
| #else |
| return uint64_t(syscall(FOLLY_SYS_gettid)); |
| #endif |
| } |
| } |