Hello list. How I can access the video memory directly from user
space? I tried to map the framebuffer (/dev/fb0) using mmap() and
ioctl(), but I have not been successful. Really I want to make a copy
of the contents of video memory and save it ?as an image. have any
suggestions?

With modern cards, the video memory is a pretty large area. In order
to find where the current screen actually resides, you will need to
know more information like what is the driver used (Linux framebuffer?
X? With what kind of card?) and probably dive into the driver code to
understand where the current screen resides. In short, this is not
impossible, but not simple neither.

For many systems (e.g. X) there are also easier solutions for getting
the contents of the current screen from user space (think of all these
screenshot programs). Anyway some more information about your context
would be helpful.

Alex.