CODEWITHSUNDEEP
vbaexcel
user3221162
user3221162

Reputation: 127

VBA out of stack error

I have several subs which call onto each other when a OnKey event is pressed. After a while, the call stack builds up and i get a "out of stack" error. Is there a method to clear the stack? Or at least end the sub when I'm not using it? EG.

Sub MoveRight()
    if GetKeyState(vbKeyDown) <0 then MoveDown
  ...
  ...
sub MoveDown
    if GetKeyState(vbKeyRight) < 0 then MoveRight
  ...
  ...
 etc

Upvotes: 1

Views: 572

Answers (3)

LegoMarine
LegoMarine

Reputation: 31

Code shown is a bit criptic, but, if you press "down" and "right" at same time, your code do a circular call between subs, that is a loop of calls that never ever returns, so stack will overflows in seconds. It will better to check keys outside subs (pseudocode):

if (key_down is pressed)
    call do_move_down
if (key_right is pressed)
    call do_move_right
...
...

Upvotes: 3

RBarryYoung
RBarryYoung

Reputation: 56745

"Out of Stack" is a Severe Fatal error. The way to clear it is to restart Excel. Though it is possible that just restarting VBA would be sufficient, I sure wouldn't trust it.

The problem here is that you have written a pair of methods with infinite recursion in them. DON'T DO THAT. The simplest general fix to this is to have your routines set static flags to prevent re-entry:

Sub MoveRight()
    Static InUse As Boolean
    If InUse Then Exit Sub
    InUse = True
    if GetKeyState(vbKeyDown) <0 then MoveDown
  ...
  ...
    InUse = False
End Sub

A more specific fix would require knowledge of what you are actually trying to do, which looks highly suspect at this point.

Upvotes: 3

MarkHone
MarkHone

Reputation: 381

You are calling into your MoveRight() and MoveDown() methods recursively.

You test calls to GetKeyState should sit outside of your stubs / event handlers.

A wider question might be why you need these calls at all if you already have the OnKey event correctly configured.

Upvotes: 0

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