c++ - POSIX 相当于 boost::thread::hardware_concurrency

Question

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Answer 1

它使用与 C 兼容的结构，那么为什么不直接使用实际代码呢？ [libs/thread/src/*/thread.cpp]

使用 pthread 库:

unsigned thread::hardware_concurrency()
{
#if defined(PTW32_VERSION) || defined(__hpux)
    return pthread_num_processors_np();
#elif defined(__APPLE__) || defined(__FreeBSD__)
    int count;
    size_t size=sizeof(count);
    return sysctlbyname("hw.ncpu",&count,&size,NULL,0)?0:count;
#elif defined(BOOST_HAS_UNISTD_H) && defined(_SC_NPROCESSORS_ONLN)
    int const count=sysconf(_SC_NPROCESSORS_ONLN);
    return (count>0)?count:0;
#elif defined(_GNU_SOURCE)
    return get_nprocs();
#else
    return 0;
#endif
}

在窗口中:

unsigned thread::hardware_concurrency()
{
    SYSTEM_INFO info={{0}};
    GetSystemInfo(&info);
    return info.dwNumberOfProcessors;
}