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emacs/lib/nproc.h
2024-01-02 09:47:10 +08:00

47 lines
1.7 KiB
C

/* Detect the number of processors.
Copyright (C) 2009-2024 Free Software Foundation, Inc.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
This file 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser 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++ */