OpenEuphoria

2. Re: BREAKing into Euphoria

• Posted by Salix <salix at fr?email.hu> Sep 11, 2007
• 2169 views

Andy Drummond wrote:
> Has anyone done this, or is there any reason why it is
> not really practical?

Usullay my scripts run faster than I can press Break. 

Adding a trace(1) line to my code always worked fine.
If I wasn't sure where to put it I simply added a 
trace_if_timeout(60) routine to the most suspicious 
loops. 

Regards,

Salix

4. Re: BREAKing into Euphoria

• Posted by Robert Craig <rds at RapidEup?oria.?om> Sep 11, 2007
• 2172 views

Andy Drummond wrote:
> Ah, but I have this enormous program and somewhere, somehow,
> it is locking up in a loop. If I went around putting in
> timeouts & traces I'd take longer than modifying the source
> for the interpreter and recompiling it and using a ctl-C or
> whatever. No, what I *need* is a way of getting the
> interpreter to enter its trace routine from keyboard use
> and not from trace(). Even then it is a problem because it
> is likely the program is not looking at the keyboard, so
> the interpreter would have to go check the keyboard itself
> for a break character.
> Apart from all that, it is likely that the loop is not supposed
> to be a loop anyway, so I wouldn't know to trace it.
> This is the ultimate cock-up cracker. I could use the profiler
> if I could get the program to stop cleanly rather than saying
> "This program is not responding - terminate anyway (Y/N)" 
> which dumps anything it had available into a black hole.
> So thanks anyway, but - I need to ask the question again.

Have you tried:
  with trace
  trace(3)

It will slow your program down,
but you'll capture the last 500 statements
in a file, ctrace.out

After forcibly killing it, you might be able to 
see in ctrace.out what it was doing when it 
became non-responsive.

Regards,
   Rob Craig
   Rapid Deployment Software
   http://www.RapidEuphoria.com

6. Re: BREAKing into Euphoria

• Posted by Pete Lomax <petelomax at blueyonder.co.?k> Sep 11, 2007
• 2153 views
• Last edited Sep 12, 2007

Andy Drummond wrote:
> 
> Ah, but I have this enormous program and somewhere, somehow,
> it is locking up in a loop. If I went around putting in
> timeouts & traces I'd take longer than modifying the source
> for the interpreter and recompiling it and using a ctl-C or
> whatever. No, what I *need* is a way of getting the
> interpreter to enter its trace routine from keyboard use
> and not from trace().

I got some "interesting" results (random crashes mainly) from this, however
enough of it works to show that something is possible (comments, Rob?):
Maybe there is a generic problem with trace in call_back routines??

-- NOTE: this is probably incompatible with allow_break/check_break().
with trace

include misc.e

constant CTRL_C_EVENT	    = 0,
	 CTRL_BREAK_EVENT   = 1

function HandlerRoutine(integer event)
    if event = CTRL_C_EVENT
    or event = CTRL_BREAK_EVENT then
trace(1)
sleep(2)
        return 1	    -- handled
    end if
    return 0		    -- not handled
end function

atom kernel32, xSetConsoleCtrlHandler, cbHR
include dll.e

    kernel32 = open_dll("kernel32.dll")

    xSetConsoleCtrlHandler = define_c_func(kernel32,"SetConsoleCtrlHandler",
{C_POINTER, --	PHANDLER_ROUTINE  pHandlerRoutine,  // address of handler
function
	 C_INT},    --	BOOL  fAdd  // handler to add or remove
	C_INT)	    -- BOOL

    cbHR = call_back(routine_id("HandlerRoutine"))
    if not c_func(xSetConsoleCtrlHandler,{cbHR,1}) then ?9/0 end if

with trace

while 1 do
    puts(1,"sleeping\n")
    sleep(2)
    puts(1,"awake\n")
end while

I suspect that if you could somehow call the trace(1) in HandlerRoutine but not
then trace any lines in that code, it might actually work.

When not interpreting source, or under an allow_break(False), then Ctrl Break
should not attempt to fire up the trace window, otherwise it should.
I don't think changing Ctrl C is a good idea, too easy to accidentally hit,
plus eg Edita happily uses it for Copy w/out problems as is.

Regards,
Pete

8. Re: BREAKing into Euphoria

• Posted by Robert Craig <rds at R?pidEu?horia.com> Sep 11, 2007
• 2143 views
• Last edited Sep 12, 2007

Pete Lomax wrote:
> 
> Andy Drummond wrote:
> > 
> > Ah, but I have this enormous program and somewhere, somehow,
> > it is locking up in a loop. If I went around putting in
> > timeouts & traces I'd take longer than modifying the source
> > for the interpreter and recompiling it and using a ctl-C or
> > whatever. No, what I *need* is a way of getting the
> > interpreter to enter its trace routine from keyboard use
> > and not from trace().
> 
> I got some "interesting" results (random crashes mainly) from this, however
> enough of it works to show that something is possible (comments, Rob?):
> Maybe there is a generic problem with trace in call_back routines??

Possibly. I'm not sure.

Regards,
   Rob Craig
   Rapid Deployment Software
   http://www.RapidEuphoria.com

10. Re: BREAKing into Euphoria

• Posted by Robert Craig <rds at Ra?idEu?horia.com> Sep 12, 2007
• 2146 views

Pete Lomax wrote:
> Robert Craig wrote:
> > Pete Lomax wrote:
> > > 
> > > I got some "interesting" results (random crashes mainly) from this,
> > > however
> > > enough of it works to show that something is possible (comments, Rob?):
> > > Maybe there is a generic problem with trace in call_back routines??
> > 
> > Possibly. I'm not sure.
> 
> I guess SetConsoleCtrlHandler is invoking the Eu code I posted much like OS
> threads, so if it is not thread-safe then random crashes will occur. Hence any
> such code would have to be in the back end rather than Eu code, unless
> something
> can be done along the lines of task_yield().

If you break out of the interpreter at a random point,
and then re-enter the interpreter, there could be problems.
It might have been in the middle of some sensitive operation
that was not completed properly.

Multitasking in Euphoria only uses one O/S thread,
and a task switch only happens at a task_yield()
so everything is safe.

Regards,
   Rob Craig
   Rapid Deployment Software
   http://www.RapidEuphoria.com

12. Re: BREAKing into Euphoria

• Posted by Andy Drummond <andy at k?strel?ele.com> Sep 12, 2007
• 2148 views

Pete Lomax wrote:
> 
> I got some "interesting" results (random crashes mainly) from this, however
> enough of it works to show that something is possible (comments, Rob?):
> Maybe there is a generic problem with trace in call_back routines??
> 
> }}}
<eucode>
> -- NOTE: this is probably incompatible with allow_break/check_break().
> with trace
> 
> include misc.e
> 
> constant CTRL_C_EVENT	    = 0,
> 	 CTRL_BREAK_EVENT   = 1
> 
> function HandlerRoutine(integer event)
>     if event = CTRL_C_EVENT
>     or event = CTRL_BREAK_EVENT then
> trace(1)
> sleep(2)
>         return 1	    -- handled
>     end if
>     return 0		    -- not handled
> end function
> 
> atom kernel32, xSetConsoleCtrlHandler, cbHR
> include dll.e
> 
>     kernel32 = open_dll("kernel32.dll")
> 
>     xSetConsoleCtrlHandler = define_c_func(kernel32,"SetConsoleCtrlHandler",
> 	{C_POINTER, --	PHANDLER_ROUTINE  pHandlerRoutine,  // address of handler
> function
> 	 C_INT},    --	BOOL  fAdd  // handler to add or remove
> 	C_INT)	    -- BOOL
> 
>     cbHR = call_back(routine_id("HandlerRoutine"))
>     if not c_func(xSetConsoleCtrlHandler,{cbHR,1}) then ?9/0 end if
> 
> with trace
> 
> while 1 do
>     puts(1,"sleeping\n")
>     sleep(2)
>     puts(1,"awake\n")
> end while
> </eucode>
{{{

> 
> I suspect that if you could somehow call the trace(1) in HandlerRoutine but
> not then trace any lines in that code, it might actually work.
> 
> When not interpreting source, or under an allow_break(False), then Ctrl Break
> should not attempt to fire up the trace window, otherwise it should.
> I don't think changing Ctrl C is a good idea, too easy to accidentally hit,
> plus eg Edita happily uses it for Copy w/out problems as is.
> 
> Regards,
> Pete

Pete,
That look pretty much what I was after. I understand that it might well not be 
possible to trace once the break has been executed, but if I can tell where I
am in the program then I can start the safer but more laborious technique of 
putting in trace(1) - or even trace(3) - calls. At present I have no idea
where I am executing when everything dies on me. I just need to go Click!
and find out which line of the program was executing at the time.
We will see...
Andy

14. Re: BREAKing into Euphoria

• Posted by Pete Lomax <petelomax at bluey?nd?r.co.uk> Sep 12, 2007
• 2155 views

Andy Drummond wrote:
> Yes, well, I see what you mean now. The control-C or control-Break keys do
> indeed break the program but there is no evidence that it ever reaches the
> code you sent. So ... not much further forward.

What I get here, not every time though, is a partial/garbled trace window and
fatal exception, eg http://palacebuilders.pwp.blueyonder.co.uk/break.gif
Nevermind, I'll email you privately if I get any further with this.

Regards,
Pete

16. Re: BREAKing into Euphoria

• Posted by Matt Lewis <matthewwalkerlewis at ??ail.com> Sep 12, 2007
• 2162 views

Pete Lomax wrote:
> 
> Andy Drummond wrote:
> > Yes, well, I see what you mean now. The control-C or control-Break keys do
> > indeed break the program but there is no evidence that it ever reaches the
> > code you sent. So ... not much further forward.
> 
> What I get here, not every time though, is a partial/garbled trace window and
> fatal exception, eg <a
> href="http://palacebuilders.pwp.blueyonder.co.uk/break.gif">http://palacebuilders.pwp.blueyonder.co.uk/break.gif</a>
> Nevermind, I'll email you privately if I get any further with this.

Yes, the problem, as you previously sorta mentioned, is that windows creates
a new thread and uses that thread to call the handler.  It's probably 
fairly straightforward to manage this in a thread-safe way within the 
C-backend, but I don't see a nice way to do this in a purely Eu-based
fashion.

I think the way to go is to use trace(3) (was about to post it until I
noticed that Rob beat me to it).

As for having to put "with trace" everywhere:  You'd have to do this 
regardless (the top of your main would work, unless you have any
"without trace" statements elsewhere in your code.  Otherwise, Euphoria
doesn't generate the IL that drives the trace screen.

trace(3) is clearly the way to go.  Let it run for a while, and check out
the file.  It should be numbingly repetitive if you're really in an 
infinite loop.  You may want/need to "without trace" some library routines
to cut down on the noise.  Even better, only enable tracing in routines
that use while or for loops.  You could probably make an automated tool
to insert/remove the with/without statements, assuming you've got a lot
of code/files to deal with.

Matt

18. Re: BREAKing into Euphoria

• Posted by Matt Lewis <matthewwalkerlewis at gma?l.co?> Sep 12, 2007
• 2209 views

Andy Drummond wrote:
> 
> Yes, I am pretty sure I'm going to have to do just that. I suppose with
> a fairly quick PC even trace(3) shouldn't make it unusable. I may create
> a mind-blowingly enormous file, though, unless Rob has been especially
> clever.

It will probably seem really slow.  But you should only need to do that once,
and then you can zero in on the problem.  The file never grows beyond a
certain size (~40K) since it only saves a total of 500 lines.  Check
out the docs for more details, but it should be pretty obvious once you
start using it.  Just search the file for "THE END" to see where it 
stopped logging.

Matt

20. Re: BREAKing into Euphoria

• Posted by abuaf Feb 08, 2022
• 1765 views

An update. Dont mind the cd lib stuff. Shows usage of iupmglplot. Also shows how to drastically reduce IUP message polling CPU by reduced polling during idleness.

 
with define DEBUG_TYPE	--popup debugger after type check failures otherwise comment out for the normal crash 
 
include euphoria/debug/debug.e 
include std/math.e 
include std/console.e 
include std/os.e 
--include dll.e 
--include machine.e 
 
include gui/iup/iup.e 
include gui/iup/iup_config.e 
include gui/iup/iup_mglplot.e 
/* 

include gui/iup/cd.e 
include gui/iup/cdiup.e 
*/ 
 
 
constant user32 = open_dll( "user32" ) 
constant xSetForegroundWindow = define_c_func( user32, "SetForegroundWindow", {C_ULONG}, C_UINT	) -- BOOL SetForegroundWindow(HWND) 
constant xGetForegroundWindow = define_c_func( user32, "GetForegroundWindow", {}, C_UINT	) -- HWND GetForegroundWindow(void) 
atom focusOld=0		 --start with NULL (invalid) 
atom debugTime=0 
 
procedure traceOn(integer val) 
	poke4(0x5b1a20, val)	 --ie TraceOn=val 
	poke4(0x5b1440, 1)		 --color_trace = TRUE;	--ie ensures the debugger pops up in color (not static uninit value of 0 ie B/W) 
end procedure 
 
 
global procedure goDebug(integer focusDebug)	--go to the debugger at the next trac'able line 
	focusOld=c_func(xGetForegroundWindow)		--save the current focus'ed win handle 
	debugTime=time() 
	if focusDebug then 
		c_func(xSetForegroundWindow, {hCon} ) 
	else	-- don't want to set focus to debugger; ie waiting for some iup gui user activity to enter trace'able code, so 
	end if				--switch to (debugger) console window 
	traceOn(1)		--TraceOn=1 ie trace out to the debugger at next "with trace" code. 
end procedure 
 
global procedure tr(object condition={}, sequence errorMessage={}) 
--atom condition <> 0, then print errorMessage, else ignore. Eg tr(1>0, {"%s %d", "five=", 5}) 
--string 'condition' for simple error message 
	if atom(condition) and condition = 0 then return end if				 --failed condition if its numeric 
	if length(errorMessage) >= 2 and sequence(errorMessage[1]) then	--formatting string, args ... 
			errorMessage=sprintf(errorMessage[1], errorMessage[2..$]) 
	end if 
	if atom(condition) then 
		condition=sprintf("%d", condition) 
	elsif length(condition) then 
		errorMessage=sprintf("%s %s", {condition, errorMessage}) 
		condition="" 
	end if 
	if length(errorMessage) or length(condition) then --non-empty string, so elaborate error 
		printf(1, "\ntr(%s): %s\n", {condition, errorMessage}) 
	end if 
	goDebug(1) 
end procedure 
 
 
 
atom breakTime=0 
 
function breakFunc(integer event) 
	puts(1, "Break pressed... ") 
	breakTime -= time() 
	if breakTime > -1	then 
		traceOn(0)	--cancel trace out to debugger (set first press), so terminate immediately 
		puts(1, "quick break repeat; exiting app...\n") 
		return 0		--Quickly repeated break, so act as if break not handled by this fn, ie pass on to next handler (eu terminates) 
	end if 
	breakTime = time()		--update timestamp 
	goDebug(1) 
	return 1	--handled the control signal so return TRUE for no further action. 
end function 
 
 
 
without trace		--we dont trace inside type checks 
ifdef DEBUG_TYPE then	 -- pinpoints the type error location with the debugger 
	function typeEnd() 
			goDebug(1)		--popup the debugger at the next traceable line 
			return 1			--no type abort; continue running 
	end function 
elsedef 
	function typeEnd() 
		return 0	--abort with type check error 
	end function 
end ifdef 
 
 
type Ihandle(atom x) 
	if x>NULL then	--ok positive 
		if trunc(x) = x then return 1 end if		 --no fractional part so x ok so continue running 
	end if 
	printf(1, "type Ihandle: bad value %d\n", {x}) 
	return typeEnd() 
end type 
 
type cdCanvas(atom x) 
	if x>NULL then	--ok positive 
		if trunc(x) = x then return 1 end if		 --no fractional part so x ok so continue running 
	end if 
	printf(1, "type cdCanvas: bad value %d\n", {x}) 
	return typeEnd() 
end type 
 
type cdContext(atom x) 
	if x>NULL then	--ok positive 
		if trunc(x) = x then return 1 end if		 --no fractional part so x ok so continue running 
	end if 
	printf(1, "type cdContext: bad value %d\n", {x}) 
	return typeEnd() 
end type 
 
with trace 
 
Ihandle plot 
 
 
function k_any( Ihandle self, atom c ) 
	tr(c='q', {"Debugging IUP client callback, c=%d", c}) 
	return IUP_DEFAULT 
--	return IUP_IGNORE 
end function 
 
function action( Ihandle self, integer c, atom after ) 
	if (c) then 
	end if 
	return K_asterisk 
end function 
 
--atom kernel32, xSetConsoleCtrlHandler, cbHR 
atom xSetConsoleCtrlHandler, cbHR 
 
 
procedure noIup() 
	integer key 
	while 1 do 
		puts(1,"sleeping press q to quit, break to debug\n") 
		sleep(2) 
		key=get_key() 
		printf(1,"awake, key=%d\n", {key}) 
		if key = 'q' then 
			exit 
		end if 
	end while 
end procedure 
 
 
 
function iupStart( object argc, object argv ) 
	IupOpen( argc, argv ) 
 
	IupMglPlotOpen()    --init IupMGLPlot library 
	plot = IupMglPlot()		--creates a empty initial data set 
	IupMglPlotBegin(plot,2) 
	for i=1 to 70 do 
		IupMglPlotAdd2D(plot, i, i*i) 
	end for 
	{}=IupMglPlotEnd(plot)		--puts the plot data into _plot. Now we can use IupSetAttribute() to modify plot data 
--	IupSetAttribute(text, "SIZE",	"200x") 
--	IupSetCallback(text, "ACTION", Icallback("action")) 
--	IupSetCallback(text, "K_ANY", Icallback("k_any")) 
	--IupSetAttribute(plot, "AXS_X", "NO")	--ok 
	--IupSetAttribute(plot, "LEGEND", "YES")	--ok 
	--IupSetAttribute(plot, "GRID", "XY")	--ok 
	IupSetAttribute(plot, "DS_COLOR", "255 0 255")	--ok  "R G B" 
	IupSetAttribute(plot, "DS_MODE", "BAR")	--ok 
	IupSetAttribute(plot, "REDRAW", NULL) 
 
/* 

	Ihandle iCanvas = IupCanvas()		--Ihandle *cnvs 
--		cdcanvas = cdCreateCanvas( CD_IUP, cnvs );	--static cdCanvas *cdcanvas .   H:\dl\graphics\CanvasDraw\v5.9\cd-5.9_Sources.zip;cd\include\cd.h;  cdCreateCanvas(cdContext *context, void *data); 
	cdContext ctx=CD_IUP() 
	cdCanvas canvas = cdCreateCanvas(ctx, iCanvas )	--static cdCanvas *cdcanvas .   H:\dl\graphics\CanvasDraw\v5.9\cd-5.9_Sources.zip;cd\include\cd.h;  cdCreateCanvas(cdContext *context, void *data); 
	cdCanvasForeground(canvas, CD_BLUE) 
--	cdCanvasLineWidth(canvas, 3); 
--	cdCanvasLineStyle(canvas, CD_CONTINUOUS); 
	cdCanvasRect(canvas, 0, 200, 0, 200) 
--	cdKillCanvas(canvas) 
	--	IupMglPlotNewDataSet(plot, 2)	--create another data set 
*/ 
 
	Ihandle dlg = IupDialog(plot)	--create a dialogue element to put the plot into 
	IupSetAttributes(dlg, "RASTERSIZE=640x480") 
	IupSetAttribute(dlg, "TITLE", "temperature/moisture") 
 
--	IupSetAttribute(plot, "GRID=YES, MARGINBOTTOM=80, AXS_XTICKROTATENUMBER=YES, MARGINRIGHT=80") 
--	IupSetAttribute(plot, "READONLY", "NO") 
--    IupSetAttribute(dlg, "MARGIN", "100x100") 
 
	IupShowXY(dlg, IUP_CENTER, IUP_CENTER) 
	return EXIT_SUCCESS 
end function 
 
without trace	 --we dont want to debug iupIdle or the iup event polling loop 
atom idleSleep=0 
function iupIdle() 
	idleSleep=.11	--iup is idle so increase the polling delay 
	return IUP_DEFAULT 
end function 
 
constant kernel32 = open_dll( "kernel32.dll" ) 
constant xGetConsoleWindow = define_c_func( kernel32, "GetConsoleWindow", {}, C_ULONG ) 
atom hCon = c_func( xGetConsoleWindow, {} ), hIup=0, hCurrent=0 
 
constant xGetNumberOfConsoleInputEvents = define_c_func( kernel32, "GetNumberOfConsoleInputEvents", {C_ULONG , C_POINTER}, C_INT) 
	--HANDLE hConsoleInput, _Out_	LPDWORD lpNumberOfEventsRead 
constant dwordVar = allocate(4) 
 
------------------ CONSOLE INPUT FNs 
integer xReadConsoleInput = define_c_func( kernel32, "ReadConsoleInputW", {C_ULONG , C_ULONG, C_INT, C_POINTER}, C_INT) 
	--HANDLE hConsoleInput, _Out_	PINPUT_RECORD lpBuffer, _In_	 DWORD nLength, _Out_	LPDWORD lpNumberOfEventsRead 
if xReadConsoleInput = -1 then	-- Using "ReadConsoleInput" doesnt work, so we try this for the failed explicit "ReadConsoleInputW" 
	xReadConsoleInput = define_c_func( kernel32, "ReadConsoleInputA", {C_ULONG , C_ULONG, C_INT, C_POINTER}, C_INT) 
end if 
constant ptrInputRecord = allocate(24)	--mem block for a single INPUT_RECORD 
 
constant KEY_EVENT=1		 --EventType is a key press/release 
constant MENU_EVENT=8 
constant FOCUS_EVENT=16 
-- INPUT_RECORD typedef; abs address of record members in ptrInputRecord (ie includes +offset) 
constant EventType = ptrInputRecord+0 
	-- KEY_EVENT union; 
	constant bKeyDown=ptrInputRecord+4 
	constant wRepeatCount=ptrInputRecord+8 
	constant wVirtualKeyCode=ptrInputRecord+10 
	constant wVirtualScanCode=ptrInputRecord+12 
	constant AsciiChar=ptrInputRecord+14 
	constant dwControlKeyState=ptrInputRecord+16 
------------------ 
 
 
constant xGetStdHandle= define_c_func( kernel32, "GetStdHandle", {C_INT}, C_ULONG) 
constant hConsoleInput=c_func(xGetStdHandle, {-10} )	-- -10 = STD_INPUT_HANDLE 
if hConsoleInput = -1 then ?9/0 end if 
 
--BOOL SetConsoleTitle(char *lpConsoleTitle)		--Kernel32 
-- see	H:\dl\c\win32\console API.pdf	 EVENT_CONSOLE_CARET	 callback event . 
-- H:\dl\c\win32\WinEvents API.pdf	p608 
 
sequence cmd = command_line() 
sequence argv = cmd[3..$] 
integer argc = length( argv ), iuret 
 
 
xSetConsoleCtrlHandler = define_c_func(kernel32,"SetConsoleCtrlHandler", 
		{C_POINTER, --	PHANDLER_ROUTINE	pHandlerRoutine,	// address of handler function 
		C_INT},		--	BOOL	fAdd	// handler to add or remove 
		C_INT)			-- BOOL 
 
cbHR = call_back(routine_id("breakFunc"))	 --{’+’, id} for cdecl 
if not c_func(xSetConsoleCtrlHandler,{cbHR,1}) then ?9/0 end if 
 
--noIup()		 --test interrupting a console (without iup) loop with async break key. 
 
iupStart( argc, argv ) 
 
IupSetGlobalFunction("IDLE_ACTION", Icallback("iupIdle"))	 --iup will call this idle callback so we can flag when iup is idle and reduce polling freq 
 
--	IupMainLoop()	 --blocks this foreground process until user closes GUI 
loop do		 --iup event polling loop 
	printf(1, "Press break to debug ") 
	? idleSleep & hCon & hIup & hCurrent & date() 
	sleep(idleSleep) 
	----- peek into the keyboard queue for debugger keyboard code sent from external app (NB: we dont use get_key() because onTrace=1 which will cause long delays until the next tracable line occurs and the debugger starts) 
	if not c_func(xGetNumberOfConsoleInputEvents, {hConsoleInput, dwordVar} )	then ?9/0 end if 
	for i = 1 to peek4s(dwordVar) do	--read each event (if > 0) 
		{}=getKey() 
	end for 
	----- 
	hCurrent=c_func(xGetForegroundWindow) 
	if hCurrent != hCon then 
		hIup=hCurrent 
	end if 
	if focusOld then	--old window focus before debugger invoked 
		if focusOld = hCon then focusOld=hIup end if	--debugging IUP window, so reject hCon 
		if focusOld != hCurrent and time()-debugTime > 0.3 then 
			--old windows not focussed and been some time (stuck in the debugger outside this block) since debugTime updated. 
			{}=c_func(xSetForegroundWindow, {focusOld} )	--focus the old windows 
			focusOld =0	 --and finnished refocusing old window, so invalidate (NULL) 
		end if 
		debugTime=time()		--update time last in this block 
	end if 
	idleSleep=.01			--do a short sleep for good user interaction speed, unless iup becomes idle and calls iupIdle() which will set a longer sleep to reduce CPU wastage 
	--IupSetAttribute(plot, "REDRAW", NULL) 
	until IupLoopStep() = IUP_CLOSE	-- poll and execute next iup event (if any). This will also call iupIdle() if iup gui event queue is idle 
end loop 
IupClose() 
 
function getKey()	--get_key() replacement, that doesnt pause 
	if not c_func(xReadConsoleInput, {hConsoleInput , ptrInputRecord, 1, dwordVar})	then ?9/0 end if	--read 1 INPUT_RECORD event, NULL to store # events read. 
	-- *dwordVar stores the address of the win32 provided input record buffer 
	if peek2u(EventType) != KEY_EVENT	or not peek(bKeyDown) then				 ----ignore non-key events or key up events 
		return -1 
	end if 
	integer ch=peek(AsciiChar) 
	if ch = 3 then		 --external global 'Alt-Break' Autohotkey script attached to our console and sent break key (useful since we dont loose gui focus) 
		goDebug(1) 
	elsif ch = 0 then		 --a control key 
		return -1	 --ignore 
	end if 
--	? ch 
	return ch 
end function 
 

22. Re: BREAKing into Euphoria

• Posted by ghaberek (admin) Feb 08, 2022
• 1755 views

Wow. So much going on here. Please don't put huge blocks of code in posts. It's too easy to get lost scrolling up-and-down through code. Use Pastey for one-off code sharing or, better yet, put together a project on GitHub and share it here.

While this is a clever idea, Euphoria 4.1 and later has built-in support for a external debuggers. It's not fully documented yet but it's there and I strongly recommend looking at that instead of injecting assembly code. This is the kind of thing we need to see as a use case for fleshing out the external debugger support and its documentation.

• https://github.com/OpenEuphoria/euphoria/blob/master/demo/simple_debug.e
• https://github.com/OpenEuphoria/euphoria/blob/master/include/euphoria/debug/debug.e

Also I need to work on getting a the new site up and running. Very old posts should be locked automatically. We shouldn't be able to reply to threads imported from the mailing list.

-Greg

24. Re: BREAKing into Euphoria

• Posted by abuaf Feb 26, 2022
• 1557 views

What's the easiest way to contribute the TraceOn functionality patches to euphoria 4.1 source? I had a closer look at "external debugger" api, doesn't seem to provide this functionality to queue a "TraceOn=1" trap out to the debugger at the next traceable code, which is great for pin pointing type checks (or async break key interruption). However the API is useful in this case to get the call stack when the non-traceable 'interruption' occurs, and then locate where the type check failed. Would break key 'interruption' in win32's seperate thread have a valid Euphoria call stack context, or is the thread anonymous without a Euphoria call context? In this case, is it even safe to run euphoria code (it seems to work) in the break handler thread, since I thought Euphoria is not multi-threaded, but one assumes that Euphoria callbacks are 'thread safe' even when they occur part way through a Euphoria byte code instruction.

26. Re: BREAKing into Euphoria

• Posted by ghaberek (admin) Feb 26, 2022
• 1507 views
• Last edited Feb 28, 2022

So much for that, I already figured it out. Turns out it was pretty easy, but I'm still not sure how safe this is. The SIGINT (Ctrl+C) signal interrupt handler is configured in InitExecute(). The first step was to borrow some code from trace_command() and plop that into INT_Handler().

// be_rterror.c:1668 
void INT_Handler(int sig_no) 
/* control-c, control-break */ 
{ 
	UNUSED(sig_no); 
	if (trace_enabled) { 
		/* start tracing */ 
		signal(SIGINT, INT_Handler); 
		TraceOn = TRUE; 
		color_trace = TRUE; 
#ifdef _WIN32 
		show_console(); 
#endif 
		return; 
	} 
	... 

This worked great... when with trace was enabled. Turns out trace_enabled is always set to TRUE and the backend relies on the frontend to emit the necessary tracing ops. So my trick would act like allow_break(FALSE) without trace enabled. My solution was to grab trace_enabled from the parser section for with/without trace and pass that through to the backend.

-- global.e:617 
export integer trace_enabled = FALSE 

Edit: I made a small change here. Originally, trace_enabled would turn on-and-off depending on the last with/without trace statement. That's not going to work since tracing would be ignored if the last check was without trace, and any omitted tracing ops would be ignored. This makes trace_enabled "sticky" in that it will only ever turn on and won't ever turn off.

-- parser.e:4529 
... 
elsif equal(option, "trace") then 
	if not BIND then 
		OpTrace = on_off 
	--	trace_enabled = on_off 
		if on_off then 
			trace_enabled = TRUE 
		end if 
	end if 
... 

-- backend.e:285 
machine_proc(65, { 
	... 
	trace_lines, 
	trace_enabled, 
	$ 
}) 

// be_machine.c:2842 
object start_backend(object x) 
/* called by Euphoria-written front-end to run the back-end 
 * 
 * x is {symtab, topcode, subcode, names, line_table, miscellaneous } 
 */ 
{ 
	... 
	trace_lines = get_pos_int(w, *(x_ptr->base+16)); 
	trace_enabled = get_pos_int(w, *(x_ptr->base+17)); 
	... 

That seems to do the trick. I made a simple little program that goes into a loop for 60 seconds and when I press Ctrl+C it jumps into the trace screen. Pressing q resumes execution until I press Ctrl+C again to jump back to trace, and pressing Q resumes execution and disables trace. Pressing Ctrl+C again from there stops the program normally.

include std/os.e 
 
with trace 
 
atom t0 = 0 
atom t1 = time() 
atom t2 = t1 + 60 
 
while t1 < t2 do 
 
    if t1 > t0 then 
        t0 = t1 
        ? t0 
    end if 
 
    sleep(rand(10)/100) 
    t1 = time() 
 
end while 

This is a pretty neat feature to have, but I'll say it again loudly: I don't know enough about the interpreter yet to say how safe this is. Your app might crash. Weird things might happen.

-Greg

28. Re: BREAKing into Euphoria

• Posted by ghaberek (admin) Feb 26, 2022
• 1505 views

Yes you're right. Sorry I missed that. But even without assembly code, poking directly at random memory addresses is bad. The correct way to do this is either in via the backend, as I've implemented above, or via the external debugger API, which I'll work on adapting to better accommodate this feature. I was busy digging into this and we both ended up replying at the same time. Hopefully what I posted above shows some progress towards this feature.

-Greg

30. Re: BREAKing into Euphoria

• Posted by abuaf Feb 27, 2022
• 1504 views

// be_rterror.c:1668 
void INT_Handler(int sig_no) 
/* control-c, control-break */ 
{ 
	UNUSED(sig_no); 
	if (trace_enabled) { 
		/* start tracing */ 
		signal(SIGINT, INT_Handler); 
		TraceOn = TRUE; 
		color_trace = TRUE; 
#ifdef _WIN32 
		show_console(); 
#endif 
		return; 
	} 
	... 

I'm not sure why you have conditioned TraceOn with " if (trace_enabled) {" . Does then mean Ctrl-C gets ignored when in "without trace" code sections? If this is the case, then this defeats the objective of a debugger allowing interruption of the program. What is desired is defferal (queuing) of the interruption until the next "with trace" section. Can you test this by adding a loop in "without trace" section and pressing break while there in the code below?

include std/os.e 
 
without trace 
function untracable() 
   puts(1, "Untraceable press break now") 
   sleep(4) 
end function 
 
with trace 
 
atom t0 = 0 
atom t1 = time() 
atom t2 = t1 + 60 
 
while t1 < t2 do 
 
    if t1 > t0 then 
        t0 = t1 
        ? t0 
    end if 
 
    sleep(rand(10)/100) 
    t1 = time() 
    untracable() 
end while 

I modified eu 3.1 DOS source to do this about 10 years ago on a big program, never any problem. In a way it cannot cause a problem, since it doesnt modify eu byte code execution in any way other than what it originally is designed to do. The break-key win32 event callback occurs in the backend; this already happens and is compeletely normal and C thread safe since it happens in C. The issue is "is it safe to run a eu callback from a win32 event thread callback (in the backend)?" To really test this, need to run a eu CRC routine while a high-frequency win32 multimedia timer event is firing. The aim is to test arbitrary eu byte code execution interruption - even during partial execution of a byte code - because that is what will happen. I suspect this is not safe, unless the eu callback dispatch code has special byte code thread saving. I havent examined the code for many years, but 99% doubt it has any thread saving. But you never know. This is why i originally used ASM to sidestep this uncertainty. Alternatively we can ask "Is there any other eu libs/code etc that handles win32 callback events - eg win32 sound multimedia playback callback from a buffer? Eg EuSDL2-master but i think the sound is fully handled in the C DLL. If a euphoria sound buffer fill callback supported then this can be tested. IUP must be doing this because as it uses the winProc gui callback originating in the DLL and then propogating to eu callbacks. But maybe they cheat and queue this type of callback, and do polling in euphoria code to dispatch the eu callback safely from euphoria. Someone want to check all this?

32. Re: BREAKing into Euphoria

• Posted by ghaberek (admin) Feb 28, 2022
• 1452 views

LOL well I meant, you designed it and I implemented it. If we release with this feature you'll surely be credited for the contribution.

No not yet, but it's a relatively small change so if I can determine it's safe to use then I can push the change to the repo soon.

For this? No. You're right that there's no need to have an external debugger trigger the internal trace screen; it should implement its own trace-like interface.

Right, and that got me thinking about complex with/without trace scenarios. I made a small addition to the changes I listed above in parser.e to help with this.

FYI Matt wrote the external debugger API for Euphoria 4.1 several years ago. I think I've got a pretty good handle on how it works and I'd very much like to improve on it.

I think the best answer is "both?" What the external debugger API does is allow you to add hooks into some existing functions that already exist in the backend. For example, when the backend encounters a trace op, it calls DebugScreen() to flip over to the trace screen you see now. You can implement your own DebugScreen() to be called instead, and that can be whatever you want. From there, you can query the symbol table and the call stack, etc. You can also inject trace statements to act as break points. I'm hoping to use this to implement full-on external debugging in my vscode-extension extension.

Well, this is its own problem altogether and not specific to the trace screen. Your ex.err dumps are going to be full of non-string sequences as well. I know in Phix, Pete has implemented strings as their own dedicated type. I think that would be more complicated with Euphoria but I'm exploring options of expanding the type system to be a little "smarter" than it is today. In the meantime, I'm hoping to at least improve the "pretty print" functionality that's used in trace and ex.err to prefer string-like output, and possibly have a way to disable this. (Something like without pretty_errors)

That's a good idea. I'll look into that along with your 'p' suggestion below.

(Long thread; replies continued below.)

-Greg