Line of unknown length

[Redisha]

Hello. I'm new here, so forgive me if I ask a very basic question.
I want to draw line of unknown lenght, so I'm using 2point (li)
I click to start the line and the line can go anwhere. Is there a way to constrain it, vertically, or horizontally?
Thanks

[andrew]

Have a look at snap restrictions:
http://www.ribbonsoft.com/qcad/manual_r ... 14.html#10