在实际的项目中，尤其是服务器端，需要多线程来处理业务，我们除了可以在配置文件中配置thread number，还可以根据系统CPU 数目来确定甚至是分配线程数。
int GetProcessorNum()
{
FILE *fstream=NULL;
char buff[1024];
memset(buff,0,sizeof(buff));
if (NULL == (fstream = popen("grep 'processor' /proc/cpuinfo | sort -u | wc -l", "r")))
{
return -1;
}
fgets(buff, sizeof(buff), fstream);
int kProcessorNum = atoi(buff);
pclose(fstream);
printf("GetProcessorNum = [%d].\n", kProcessorNum);
return kProcessorNum ;
}