C++ uuid_generate time cost

//Util.h
#ifndef Util_H
#define Util_H
#include <functional>
#include <iostream>
#include <mysql/mysql.h>
#include <random>
#include <sstream>
#include <string.h>
#include <thread>
#include <uuid/uuid.h>
#include <vector>
#include "Model/Geeks.h"
#include "Model/Parent.h"
#include "Model/BookStruct.cpp"

class Util
{
public:
    static char *uuidValue;
    static char *dtValue; 
    void testTimeUuid(int loops);
    char *getUuid();
   void printTimeCost13(chrono::time_point<chrono::system_clock> startTime, chrono::time_point<chrono::system_clock> endTime);
};

#endif

 

//Util.cpp

#include "Model/Util.h"

char *Util::uuidValue = (char *)malloc(40);
char *Util::dtValue = (char *)malloc(20);

void Util::testTimeUuid(int loops)
{
    int interval=1000000;
    chrono::time_point<chrono::system_clock> startTime;
    chrono::time_point<chrono::system_clock> endTime;
    for(int i=0;i<loops;i++)
    {
        startTime=chrono::system_clock::now();
        for(int j=0;j<interval;j++)
        {
            getUuid();
        }
        endTime=chrono::system_clock::now();
        cout<<"Loop="<<i<<endl;
        printTimeCost13(startTime,endTime);
    }
}

char *Util::getUuid()
{
    uuid_t newUUID;
    uuid_generate(newUUID);
    uuid_unparse(newUUID, uuidValue);
    return uuidValue;
}

void Util::printTimeCost13(chrono::time_point<chrono::system_clock> startTime,
                           chrono::time_point<chrono::system_clock> endTime)
{ 
    cout <<"Time cost:"
         << chrono::duration_cast<chrono::seconds>(endTime - startTime).count() << " seconds,"
         << chrono::duration_cast<chrono::milliseconds>(endTime - startTime).count() << " milliseconds,"
         << chrono::duration_cast<chrono::microseconds>(endTime - startTime).count() << " milliseconds,"
         << chrono::duration_cast<chrono::nanoseconds>(endTime - startTime).count() << " nanoseconds!!!"
         << endl;
}

//h1.cpp

#include "Model/Util.h"

void uuidTest13(int loops);

int main(int args,char **argv)
{
    try
    {
        uuidTest13(atoi(argv[1]));
    }
    catch(const std::exception& e)
    {
        std::cerr << e.what() << '\n';
    } 
} 

void uuidTest13(int loops)
{
    Util ul;
    ul.testTimeUuid(loops);
}

Complile:

g++ -g -std=c++2a -I. *.cpp ./Model/*.cpp -o h1 -lmysqlclient -luuid -lpthread;

Execute in Win10+VMWare WorkStation Pro+Ubuntu+g++