[Yabasic-users] Malloc problem, Yabasic under Windows 98

[Steve L. <ste...@ho...>]

Hello everybody,

A few days back, I posted a question about a problem I have encountered.
Under Windows 98, yabasic cannot handle large numbers of subroutine calls
with large numbers of parameters. Virtual memeory is gradually eaten up, and
eventually the program fails with a malloc error.

I have found that the problem also happens if large numbers of subroutine
calls are made and there large numbers of local variables declared within
the subroutine. My programs call many different subroutines, each with a few
local variables. The algorithm is repeated a few hundred thousand times (its
an optimisation program for a multi-variable problem). I can reproduce the
problem with a simple piece of code which uses a single subroutine, called a
few million times. To show the fault more quickly, you can set the upper
limit for your virtual memory to say 300Mb. On my PC, that means the the
problem happens after only 75,000 subroutine calls.

Has anybody else seen this problem with local variable space not being
released? How do I resolve it?

Thanks, Steve

>>>>>>>
REM
REM Some preliminary tasks
REM
clear screen:open window 100,30:window origin "lb"

REM
REM To demo the problem, we must call a function many times
REM
for Counter = 1 to 10000000
   DoSomeWork()
   REM
   REM Display the loop counter so that we can see how far the program has
got
   REM
   clear window
   text 10,10, str$(Counter)
next Counter

REM
REM Tidy up and finish. If the fault happens, the user never gets this
far....
REM
inkey$():close window

sub DoSomeWork()
   local
a1,b1,c1,d1,e1,f1,g1,h1,i1,j1,k1,l1,m1,n1,o1,p1,q1,r1,s1,t1,u1,v1,w1,x1,y1,z
1
   local
a2,b2,c2,d2,e2,f2,g2,h2,i2,j2,k2,l2,m2,n2,o2,p2,q2,r2,s2,t2,u2,v2,w2,x2,y2,z
2
   local
a3,b3,c3,d3,e3,f3,g3,h3,i3,j3,k3,l3,m3,n3,o3,p3,q3,r3,s3,t3,u3,v3,w3,x3,y3,z
3
   local
a4,b4,c4,d4,e4,f4,g4,h4,i4,j4,k4,l4,m4,n4,o4,p4,q4,r4,s4,t4,u4,v4,w4,x4,y4,z
4
   local
a5,b5,c5,d5,e5,f5,g5,h5,i5,j5,k5,l5,m5,n5,o5,p5,q5,r5,s5,t5,u5,v5,w5,x5,y5,z
5
   local
a6,b6,c6,d6,e6,f6,g6,h6,i6,j6,k6,l6,m6,n6,o6,p6,q6,r6,s6,t6,u6,v6,w6,x6,y6,z
6
   local
a7,b7,c7,d7,e7,f7,g7,h7,i7,j7,k7,l7,m7,n7,o7,p7,q7,r7,s7,t7,u7,v7,w7,x7,y7,z
7
   local
a8,b8,c8,d8,e8,f8,g8,h8,i8,j8,k8,l8,m8,n8,o8,p8,q8,r8,s8,t8,u8,v8,w8,x8,y8,z
8
   local
a9,b9,c9,d9,e9,f9,g9,h9,i9,j9,k9,l9,m9,n9,o9,p9,q9,r9,s9,t9,u9,v9,w9,x9,y9,z
9
   REM
   REM ....here is where we would normally do lots of work....
   REM
end sub