Instructs an in-process server to create its registry entries for all classes supported in this server module. If this function fails, the state of the registry for all its classes is indeterminate.
STDAPI DllRegisterServer(void);
This function supports the standard return values E_OUTOFMEMORY and E_UNEXPECTED, as well as the following:
E_NOTIMPL is not a valid return code.
For an explanation of the requirement values, see Requirements (COM).
Windows NT/2000/XP: Requires Windows NT 4.0 or later.
Windows 95/98: Requires Windows 95 or later.
Header: Declared in olectl.h.
Library: User-defined.
STDAPI means it uses the stdcall calling convention and it returns a HRESULT.
In Delphi you can declare it as:
Uses Windows;
function DllRegisterServer: HResult;