Virtual files

The RAVL IO mechanism includes a way of accessing various system resources like they were a file, much like devices in /dev under UN*X. In RAVL all virtual devices start with the @ character. They allow you to access things like frame grabbers and the display as if it was a file.

Here's some examples:

@X and @XA Used to display images on the screen.

@V4L and @V4LH Access a video 4 linux frame grabber. (From RAVL's Contrib library)

@METEOR1 Access a meteor 1 frame grabber. (From RAVL's Contrib library)

@str Allows a string embedded in a file name to read as if it were the contents of a file. E.g. if this string is used in place of a "file name":   "@str:... some data ..." then on reading the "file", its "contents" would be:   ... some data ...