OpenEuphoria

1. Depth limit to nested for loops

• Posted by Fernando Bauer <fmbauer at hotmai?.?om> Jun 03, 2008
• 613 views

Kat wrote:
> 
> Derek Parnell wrote:
> > 
> > Kat wrote:
> > 
> > > What is the depth limit to nested for/while loops in Eu?
> > 
> > I think it is only limited by available memory. There is no hard-coded
> > limit.
> 
> When you say "available memory", would that be 1Kbytes local stack space per
> procedure, or 64k global stack space, or the 2 gigabytes the OS will let the
> program have? Or somewhere in between that's undefined?
> 
> Yes, real world, i hit TurboPascal's stack limit with nested loops.
> 
> Kat

I tested two cases with exwc 3.0.2 (WinXP SP2):

a) At top-level:

integer fn,r,depth
depth = 0
r = 0
while r = 0 do
depth += 1
position(1,1)
printf(1,"Depth: %d ",depth)
fn = open("nesttst.exw","w")
puts(fn,"integer a a = 0\n")
for i = 1 to depth do
   printf(fn,"for a%d=%d to %d do a += 1\n",i)
end for
for i = 1 to depth do
   printf(fn,"end for\n",i)
end for
puts(fn,"? a")
close(fn)
r = system_exec("exwc nesttst.exw",2)
end while
printf(1,"\nMaximum depth of nested 'for':%d\n",depth-1)
printf(1,"Return value at system_exec:%d\n",r)

Result:
Depth: 2696 A stack overflow was encountered at address 7c90edde
Maximum depth of nested 'for':2695
Return value at system_exec:-1073741819

b) Inside a procedure:

integer fn,r,depth
depth = 0
r = 0
while r = 0 do
depth += 1
position(1,1)
printf(1,"Depth: %d ",depth)
fn = open("nesttst.exw","w")
puts(fn,"integer a a = 0\nprocedure test()\n")
for i = 1 to depth do
   printf(fn,"for a%d=%d to %d do a += 1\n",i)
end for
for i = 1 to depth do
   printf(fn,"end for\n",i)
end for
puts(fn,"? a\n")
puts(fn,"end procedure\ntest()")
close(fn)
r = system_exec("exwc nesttst.exw",2)
end while
printf(1,"\nMaximum depth of nested 'for':%d\n",depth-1)
printf(1,"Return value at system_exec:%d\n",r)

Result:
Depth: 2784 2783
Maximum depth of nested 'for':2783
Return value at system_exec:-1073741819

In this case (depth=2784), the program doesn't show error message, but,
strangely, it doesn't show the value of 'a'.

Regards,
   Fernando

3. Re: Depth limit to nested for loops

• Posted by Matt Lewis <matthewwalkerlewis at ?mail.co?> Jun 03, 2008
• 575 views

Fernando Bauer wrote:
> 
> > > Kat wrote:
> > > 
> > > > What is the depth limit to nested for/while loops in Eu?

 
> I tested two cases with exwc 3.0.2 (WinXP SP2):
> 
> a) At top-level:

> Result:
> Depth: 2696 A stack overflow was encountered at address 7c90edde
> Maximum depth of nested 'for':2695
> Return value at system_exec:-1073741819
> 
> b) Inside a procedure:
 
> Result:
> Depth: 2784 2783
> Maximum depth of nested 'for':2783
> Return value at system_exec:-1073741819
> 
> In this case (depth=2784), the program doesn't show error message, but,
> strangely,
> it doesn't show the value of 'a'.

If you're using a compiled interpreter, then the interpretation will cause
a stack overflow, since it will basically call Statement_list() recursively.

Matt