What does it mean to 'read' PDF?
If you just need to 'view' the PDF file then you simply use the appropriate system function ShellExecute, indicating "open" in the parameter lpOperation:
http://allapi.mentalis.org/apilist/ShellExecute.shtml

If you distribute your applications keep in mind that:
1) no guarantees that the user's system is installed Acrobat (could have Foxit Reader or another viewer) for which the ShellExecute function is strongly recommended because it will use the viewer installed, it does not matter what it is.

2) ShellExecute is a system function present in all Windows versions, so nothing OCX / DLL to distribute and install, which they bring with them always the 'usual' version compatibility issues.