i can't use libfunctions syntax to view the functions from my dll file

i have problem in 'libfunctions' syntax. i want to view the functions from dll file, i use loadlibrary('shrlib', 'hfile') to load the h & dll file. And i check the memory of matlab which is used, then i use ilbfunctions to view ,but it snow that '*No methods for class lib.RovInterfaceDll or no class lib.RovInterfaceDll*.' RobInterfaceDll is the name of shared library file. what's wrong in my syntax?