I don't understand why.
#include "getNumberOfPhysicalCPUCores.h"
#include <Common/config.h>
#if defined(OS_LINUX)
#    include <cmath>
#    include <fstream>
#endif
#if USE_CPUID
#    include <libcpuid/libcpuid.h>
#endif
#include <thread>
#if defined(OS_LINUX)
unsigned getCGroupLimitedCPUCores(unsigned default_cpu_count)