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// OpenVPN -- An application to securely tunnel IP networks
// over a single port, with support for SSL/TLS-based
// session authentication and key exchange,
// packet encryption, packet authentication, and
// packet compression.
//
// Copyright (C) 2012- OpenVPN Inc.
//
// SPDX-License-Identifier: MPL-2.0 OR AGPL-3.0-only WITH openvpn3-openssl-exception
//
// Linux methods for enumerating the number of cores on machine,
// and binding a thread to a particular core.
#pragma once
#include <thread>
#include <openvpn/common/platform.hpp>
#if defined(__APPLE__)
#include <sys/types.h>
#include <sys/sysctl.h>
#elif defined(OPENVPN_PLATFORM_LINUX)
#include <unistd.h>
#elif defined(OPENVPN_PLATFORM_WIN)
#include <windows.h>
#endif
namespace openvpn {
inline int n_cores()
{
int count = std::thread::hardware_concurrency();
// C++11 allows thread::hardware_concurrency() to return 0, fall back
// to specific solution if we detect this
if (count > 0)
return count;
#if defined(__APPLE__)
size_t count_len = sizeof(count);
if (::sysctlbyname("hw.logicalcpu", &count, &count_len, NULL, 0) != 0)
count = 1;
return count;
#elif defined(OPENVPN_PLATFORM_LINUX)
long ret = ::sysconf(_SC_NPROCESSORS_ONLN);
if (ret <= 0)
ret = 1;
return static_cast<int>(ret);
#elif defined(OPENVPN_PLATFORM_WIN)
SYSTEM_INFO si;
::GetSystemInfo(&si);
return si.dwNumberOfProcessors;
#else
return 1;
#endif
}
} // namespace openvpn
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