boost异常 boost::filesystem::directory_iterator::construct: Not a directory

如果给boost::filesystem::path传入的字符串，没有判断该path的类型，就生成boost::filesystem::directory_iterator就会抛出该异常

假定字符串pPath为文件，下面代码产生异常

        path pathDir(pPath);
        directory_iterator itrItem(pathDir);

将其修正为：

path pathDir(pPath);
if (is_directory(pathDir))
{
	directory_iterator itrItem(pathDir);
}