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- /*
- * Copyright 2016-present 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
- }
- } // namespace folly
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