Text Formatting ⇒ underline length

[nosabicu]

Hi there,
I have a question about underline:basically I want to get the effect that make the underline span all the textwidth, is there anyway to achieve it?
I search lots of solution, no luck.
Thanks a lot.

[Ijon Tichy]

Underline of what? Usually \underline{foo} underlines foo. So if foo spans the textwidth, the underline would span the textwidth. But perhaps you are searching for something completely different, e.g., how to underline the page head or how to have a horizontal line in a tabular or …

So please, explain what you really try to achieve. And please try to illustrate that problem with a minimal working example, that can be used to reproduce your problem. Helpers usually need such a minimal working example also to experiment and show a suggestion.