本文介绍了以编程方式查找机器上的内核数的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

有没有办法以独立于平台的方式从 C/C++ 确定一台机器有多少个内核?如果不存在这样的东西，那么按平台(Windows/*nix/Mac)确定它怎么样?

Is there a way to determine how many cores a machine has from C/C++ in a platform-independent way? If no such thing exists, what about determining it per-platform (Windows/*nix/Mac)?

C++11

#include <thread>

//may return 0 when not able to detect
const auto processor_count = std::thread::hardware_concurrency();

参考:std::thread::hardware_concurrency

在 C++11 之前的 C++ 中，没有可移植的方式.相反，您需要使用以下一种或多种方法(由适当的 #ifdef 行保护):

In C++ prior to C++11, there's no portable way. Instead, you'll need to use one or more of the following methods (guarded by appropriate #ifdef lines):

Win32

SYSTEM_INFO sysinfo;
GetSystemInfo(&sysinfo);
int numCPU = sysinfo.dwNumberOfProcessors;

Linux、Solaris、AIX和MacOSX>=10.4(即Tiger以上)

int numCPU = sysconf(_SC_NPROCESSORS_ONLN);

FreeBSD、MacOSX、NetBSD、OpenBSD等

int mib[4];
int numCPU;
std::size_t len = sizeof(numCPU); 

/* set the mib for hw.ncpu */
mib[0] = CTL_HW;
mib[1] = HW_AVAILCPU;  // alternatively, try HW_NCPU;

/* get the number of CPUs from the system */
sysctl(mib, 2, &numCPU, &len, NULL, 0);

if (numCPU < 1) 
{
    mib[1] = HW_NCPU;
    sysctl(mib, 2, &numCPU, &len, NULL, 0);
    if (numCPU < 1)
        numCPU = 1;
}

HPUX

int numCPU = mpctl(MPC_GETNUMSPUS, NULL, NULL);

IRIX

int numCPU = sysconf(_SC_NPROC_ONLN);

Objective-C(MacOSX>=10.5或iOS)

NSUInteger a = [[NSProcessInfo processInfo] processorCount];
NSUInteger b = [[NSProcessInfo processInfo] activeProcessorCount];

这篇关于以编程方式查找机器上的内核数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！

本站部分内容来源互联网,如果有图片或者内容侵犯您的权益请联系我们删除！

以编程方式查找机器上的内核数