[GRASSLIST:4804] Re: v.digit and other interactive commands

[Glynn Clements]

Hamish wrote:

> > This is probably not related to the last couple of posts on v.digit 
> > crashing... but it seems like a lot of the interactive programs like
> > v.digit will send my processor useage up to near 100% when it is
> > waiting for user input... 
> > 
> > Any ideas?
> 
> 
> yeah.. the code which waits for you to press a mouse button is a loop. 
> Usually you would have it sleep for a tenth of a second between
> checking, but the usleep() function in the C library isn't portable
> across all the computing platforms that GRASS supports.
> 
> There is one called sleep() which will work on everyones' systems, but
> it will only let the system go to sleep for 1 second at a time which
> makes reaction time way too slow. So we just leave it checking as fast
> as the computer can check, which is why you are pegged at 100%.
> 
> annoying but harmless for the most part.
> 
> Note that d.zoom from the command line in 5.3 is fine, in 5.7 it is not.
> 5.7's d.what.vect is especially bad at this.
> 
> This is even worse when you are running grass remotely over the network.
> 
> 
> suggestions for fixing this are welcome..

Use select() on both the X connection and the monitor socket. See
Get_Xevent() in Serve_Xevent.c.

-- 
Glynn Clements <glynn at gclements.plus.com>