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+/* Detect the number of processors.
+
+ Copyright (C) 2009-2020 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Glen Lenker and Bruno Haible. */
+
+/* Allow the use in C++ code. */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* A "processor" in this context means a thread execution unit, that is either
+ - an execution core in a (possibly multi-core) chip, in a (possibly multi-
+ chip) module, in a single computer, or
+ - a thread execution unit inside a core
+ (hyper-threading, see <https://en.wikipedia.org/wiki/Hyper-threading>).
+ Which of the two definitions is used, is unspecified. */
+
+enum nproc_query
+{
+ NPROC_ALL, /* total number of processors */
+ NPROC_CURRENT, /* processors available to the current process */
+ NPROC_CURRENT_OVERRIDABLE /* likewise, but overridable through the
+ OMP_NUM_THREADS environment variable */
+};
+
+/* Return the total number of processors. The result is guaranteed to
+ be at least 1. */
+extern unsigned long int num_processors (enum nproc_query query);
+
+#ifdef __cplusplus
+}
+#endif /* C++ */