Created attachment 78414 [details] [review]
patch to fix problem

Not sure that defaulting y to 0 if Yscale is 0 is the right solution here, but it
at least makes the code work okay.  If more research is needed (e.g. if Yscale should never be 0), then let me know.

Same thing happens on ubuntu feisty.

Oops, note the patch call GetLongParameter(LP_YSCALE) twice (once when setting lp_yscale and again in th else).  Probably better to just re-use lp_ypscale variable in the else since we already read the value into the static variable.  I won't reattach an updated patch since this is easy enough to fix.  Also, I suspect that the "correct" way to fix this problem might be to default y to something else since dividing by a small number makes a big number, not a number close to 0.  So not sure what the default value should be when LP_YSCALE is 0, but should add some code to protect against divide by zero here, obviously.

So I suspect this patch probably needs a bit of work by someone who understands what the code actually is doing.

Program received signal SIGFPE, Arithmetic exception.
[Switching to Thread -1226971440 (LWP 5195)]
0x0807c325 in CDasherControl::TimerEvent ()

i can reproduce this under archlinux being dasher pkgmaintainer in arch and trying to upgrade from 4.2.0 -> 4.3.2

Thanks for the patches - it's fixed now in CVS, and I'll be releasing tomorrow.