Re: Stalls in idle loop

[Havoc Pennington <hp redhat com>]

Nick Matsakis <matsakis@merl.com> writes: 
> #0  0x4031d17e in __select () from /lib/libc.so.6
> #1  0x40251dd8 in ?? () from /usr/X11R6/lib/libX11.so.6
> #2  0x401e18f8 in _XRead () from /usr/X11R6/lib/libX11.so.6
> #3  0x401e135d in _XEventsQueued () from /usr/X11R6/lib/libX11.so.6
> #4  0x401d58ea in XPending () from /usr/X11R6/lib/libX11.so.6
> #5  0x40153359 in gdk_event_prepare () from /usr/lib/libgdk-1.2.so.0
> #6  0x4018349a in g_main_iterate () from /usr/lib/libglib-1.2.so.0
> #7  0x401838f1 in g_main_run () from /usr/lib/libglib-1.2.so.0
> #8  0x400a85b9 in gtk_main () from /usr/lib/libgtk-1.2.so.0
> #9  0x8055453 in main ()
> #10 0x402889cb in __libc_start_main (main=0x8055260 <main>, argc=1, 
>     argv=0xbffffaa4, init=0x804a084 <_init>, fini=0x805577c <_fini>, 
>     rtld_fini=0x4000ae60 <_dl_fini>, stack_end=0xbffffa9c)
>     at ../sysdeps/generic/libc-start.c:92
>

This is just your app sitting in select() waiting for X
events. Standard normal stuff.
 
> It seems to me that it should continue to run your function as long as it
> is idle, and your function should be smart enough to know when it should
> be working and when it should not. You are correct that the idle function
> shouldn't take a long time to run, but I expected that the process should
> be: run the function, handle any pending events, run the function, handle
> any pending events, etc.  It doesn't seem right for the number of times
> your idle function is run to depend on how many redraw requests or
> whatever events your program gets.  In any case, that is probably not the
> problem here.  Adding the idle function more than once makes the problem
> _more likely_ to occur.
> 

Does your idle function return TRUE? If it returns FALSE it will be
removed. If it returns void then random junk will be returned,
sometimes TRUE and sometimes FALSE.

Havoc