How to use copy_file in boost::filesystem?

I want to copy a file from directory to another, but my program always aborts for some reasons.Has anyone done this this before could tell me what was wrong? And how could I catch exceptions was thrown by copy_file, I checked boost site, but I could not find any relevant information about exception.

path user_path( "C:\\My Folder" );
boost::filesystem::create_directory( user_path );
path file(  "C:\\Another\\开发者_开发知识库file.txt" );
boost::filesystem::copy_file( file, user_path );

Thanks,

You have to provide a path to a file name, not just the directory it resides in.