Question about pixel

Good Day!
In the online help, it says:
For the first version of CreatePen, if nWidth value is 0, the width in device units is always 1 pixel, regardless of the mapping mode.

now, how do I set or get the pixel size of my CDC object.
I need the info badly for my plotting/printing module project.
Thanks in advance.

You must create a pen with the pixel width you require, using CreatePen or CreatePenIndirect.

Dave