2 * Copyright 2017-present Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #include <folly/system/ThreadName.h>
19 #include <type_traits>
21 #include <folly/Portability.h>
22 #include <folly/Traits.h>
23 #include <folly/portability/PThread.h>
27 // This looks a bit weird, but it's necessary to avoid
28 // having an undefined compiler function called.
29 #if defined(__GLIBC__) && !defined(__APPLE__) && !defined(__ANDROID__)
30 #if __GLIBC_PREREQ(2, 12)
31 // has pthread_setname_np(pthread_t, const char*) (2 params)
32 #define FOLLY_HAS_PTHREAD_SETNAME_NP_THREAD_NAME 1
36 #if defined(__APPLE__) && defined(__MAC_OS_X_VERSION_MIN_REQUIRED)
37 #if __MAC_OS_X_VERSION_MIN_REQUIRED >= 1060
38 // has pthread_setname_np(const char*) (1 param)
39 #define FOLLY_HAS_PTHREAD_SETNAME_NP_NAME 1
45 #if FOLLY_HAVE_PTHREAD && !_WIN32
46 pthread_t stdTidToPthreadId(std::thread::id tid) {
48 std::is_same<pthread_t, std::thread::native_handle_type>::value,
49 "This assumes that the native handle type is pthread_t");
51 sizeof(std::thread::native_handle_type) == sizeof(std::thread::id),
52 "This assumes std::thread::id is a thin wrapper around "
53 "std::thread::native_handle_type, but that doesn't appear to be true.");
54 // In most implementations, std::thread::id is a thin wrapper around
55 // std::thread::native_handle_type, which means we can do unsafe things to
58 std::memcpy(&id, &tid, sizeof(id));
65 bool canSetCurrentThreadName() {
66 #if FOLLY_HAS_PTHREAD_SETNAME_NP_THREAD_NAME || \
67 FOLLY_HAS_PTHREAD_SETNAME_NP_NAME
74 bool canSetOtherThreadName() {
75 #if FOLLY_HAS_PTHREAD_SETNAME_NP_THREAD_NAME
82 static constexpr size_t kMaxThreadNameLength = 16;
84 Optional<std::string> getThreadName(std::thread::id id) {
85 #if FOLLY_HAS_PTHREAD_SETNAME_NP_THREAD_NAME || \
86 FOLLY_HAS_PTHREAD_SETNAME_NP_NAME
87 std::array<char, kMaxThreadNameLength> buf;
88 if (pthread_getname_np(stdTidToPthreadId(id), buf.data(), buf.size()) != 0) {
89 return Optional<std::string>();
91 return make_optional(std::string(buf.data()));
93 return Optional<std::string>();
97 Optional<std::string> getCurrentThreadName() {
98 return getThreadName(std::this_thread::get_id());
101 bool setThreadName(std::thread::id tid, StringPiece name) {
102 #if !FOLLY_HAVE_PTHREAD || _WIN32
105 name = name.subpiece(0, kMaxThreadNameLength - 1);
106 char buf[kMaxThreadNameLength] = {};
107 std::memcpy(buf, name.data(), name.size());
108 auto id = stdTidToPthreadId(tid);
109 #if FOLLY_HAS_PTHREAD_SETNAME_NP_THREAD_NAME
110 return 0 == pthread_setname_np(id, buf);
111 #elif FOLLY_HAS_PTHREAD_SETNAME_NP_NAME
112 // Since OS X 10.6 it is possible for a thread to set its own name,
113 // but not that of some other thread.
114 if (pthread_equal(pthread_self(), id)) {
115 return 0 == pthread_setname_np(buf);
125 #if FOLLY_HAVE_PTHREAD
126 bool setThreadName(pthread_t pid, StringPiece name) {
128 // Not currently supported on Windows.
132 std::is_same<pthread_t, std::thread::native_handle_type>::value,
133 "This assumes that the native handle type is pthread_t");
135 sizeof(std::thread::native_handle_type) == sizeof(std::thread::id),
136 "This assumes std::thread::id is a thin wrapper around "
137 "std::thread::native_handle_type, but that doesn't appear to be true.");
138 // In most implementations, std::thread::id is a thin wrapper around
139 // std::thread::native_handle_type, which means we can do unsafe things to
142 std::memcpy(&id, &pid, sizeof(id));
143 return setThreadName(id, name);
148 bool setThreadName(StringPiece name) {
149 return setThreadName(std::this_thread::get_id(), name);