Thanks David - that gives me ALOT to chew on.  TCL is the way to go,
huh?  ok.  In the meantime, I'll ask about my current implementation,
since I have a show and some recording to do with this instrument :) 
Hopefully I can rig it up to work in the short-term.

> 1) Try to avoid using FLTK widgets whenever possible. I know it sounds
> counterintuitive, but they always seem to crash Csound when you say,
> for example try to control button widgets with program change messages.
> There are several other things such as that that seem to contribute to
> the instability of FLTK.

This is the reason for my question, actually.  I know the FLSetVal_i
can set the value of an FLButton, so I am calling a deligate
instrument everytime I receive a button-related controller change. 
Sloppy, huh?  :)  It works, but as I said, the midiin opcode's buffer
doesn't empty after I read from it, so this delegate gets called
repeatedly.  Here's some code:

instr 31
....
inputbuttons:
inputbutton1:
if	kdata1 != 65 kgoto inputbutton2

;call instr 32 to update buttons from global values.  instr 32's note
lasts .001 secs, which is quicker than I can produce midi messages
with my controller.

event "i",32,.001,.01,1
if kdata2 != 0 kgoto inputnext1
gkloop1 = 0
inputnext1:
if kdata2 != 127 kgoto inputbutton2
gkloop1 = 1
...
endin

	instr 32	;button switcher
i1 = i(gkloop1)
i2 = i(gkloop2)
i3 = i(gkloop3)
i4 = i(gkloop4)
i5 = i(gkloopread1)
i6 = i(gkloopread2)
i7 = i(gkloopread3)
i8 = i(gkloopread4)
iset = p4
FLsetVal_i i1, gihbut1
FLsetVal_i i2, gihbut2
FLsetVal_i i3, gihbut3
FLsetVal_i i4, gihbut4
FLsetVal_i i5, gihbutread1
FLsetVal_i i6, gihbutread2
FLsetVal_i i7, gihbutread3
FLsetVal_i i8, gihbutread4
	endin



>
> 2) midiin seems to work most efficiently when encapsulated inside of a
> UDO, see
> http://www.csounds.com/udo/displayOpcode.php?opcode_id=71
> http://www.csounds.com/udo/displayOpcode.php?opcode_id=69
> http://www.csounds.com/udo/displayOpcode.php?opcode_id=68
> http://www.csounds.com/udo/displayOpcode.php?opcode_id=65
> http://www.csounds.com/udo/displayOpcode.php?opcode_id=74
I will check this path out as well.

>
> for more examples. Note that the last one of those UDO's actually takes
> the same formula for scaling as found in the source code for ctrl7, and
> thus can be quite useful when used in combination with raw midiin.
>
> In general I would suggest to start looking towards TclCsound for GUI
> display purposes. It seems much more robust and stable than the current
> FLTK implementation, as I've been having extreme difficulty making
> stable, cross-platform patches using FLTK, but not at all with
> TclCsound.

Thanks again for the help - I'll definitely be checking UDOs and TclCsound out.
b