1 /* Detect the number of processors. 2 3 Copyright (C) 2009-2021 Free Software Foundation, Inc. 4 5 This file is free software: you can redistribute it and/or modify 6 it under the terms of the GNU Lesser General Public License as 7 published by the Free Software Foundation; either version 2.1 of the 8 License, or (at your option) any later version. 9 10 This file is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public License 16 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 17 18 /* Written by Glen Lenker and Bruno Haible. */ 19 20 /* Allow the use in C++ code. */ 21 #ifdef __cplusplus 22 extern "C" { 23 #endif 24 25 /* A "processor" in this context means a thread execution unit, that is either 26 - an execution core in a (possibly multi-core) chip, in a (possibly multi- 27 chip) module, in a single computer, or 28 - a thread execution unit inside a core 29 (hyper-threading, see <https://en.wikipedia.org/wiki/Hyper-threading>). 30 Which of the two definitions is used, is unspecified. */ 31 32 enum nproc_query 33 { 34 NPROC_ALL, /* total number of processors */ 35 NPROC_CURRENT, /* processors available to the current process */ 36 NPROC_CURRENT_OVERRIDABLE /* likewise, but overridable through the 37 OMP_NUM_THREADS environment variable */ 38 }; 39 40 /* Return the total number of processors. The result is guaranteed to 41 be at least 1. */ 42 extern unsigned long int num_processors (enum nproc_query query); 43 44 #ifdef __cplusplus 45 } 46 #endif /* C++ */