1 // Copyright 2017 The Abseil Authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 // 15 // This file includes routines to find out characteristics 16 // of the machine a program is running on. It is undoubtedly 17 // system-dependent. 18 19 // Functions listed here that accept a pid_t as an argument act on the 20 // current process if the pid_t argument is 0 21 // All functions here are thread-hostile due to file caching unless 22 // commented otherwise. 23 24 #ifndef ABSL_BASE_INTERNAL_SYSINFO_H_ 25 #define ABSL_BASE_INTERNAL_SYSINFO_H_ 26 27 #ifndef _WIN32 28 #include <sys/types.h> 29 #endif 30 31 #include <cstdint> 32 33 #include "absl/base/port.h" 34 35 namespace absl { 36 ABSL_NAMESPACE_BEGIN 37 namespace base_internal { 38 39 // Nominal core processor cycles per second of each processor. This is _not_ 40 // necessarily the frequency of the CycleClock counter (see cycleclock.h) 41 // Thread-safe. 42 double NominalCPUFrequency(); 43 44 // Number of logical processors (hyperthreads) in system. Thread-safe. 45 int NumCPUs(); 46 47 // Return the thread id of the current thread, as told by the system. 48 // No two currently-live threads implemented by the OS shall have the same ID. 49 // Thread ids of exited threads may be reused. Multiple user-level threads 50 // may have the same thread ID if multiplexed on the same OS thread. 51 // 52 // On Linux, you may send a signal to the resulting ID with kill(). However, 53 // it is recommended for portability that you use pthread_kill() instead. 54 #ifdef _WIN32 55 // On Windows, process id and thread id are of the same type according to the 56 // return types of GetProcessId() and GetThreadId() are both DWORD, an unsigned 57 // 32-bit type. 58 using pid_t = uint32_t; 59 #endif 60 pid_t GetTID(); 61 62 } // namespace base_internal 63 ABSL_NAMESPACE_END 64 } // namespace absl 65 66 #endif // ABSL_BASE_INTERNAL_SYSINFO_H_ 67