Resizing a global memory block

Getting Started
1

Folks - In my module’s Properties, have declared mymemoryblock as a global memory block: mymemoryblock as memoryblock

Now I need to resize it. The Xojo documentation indicates
mymemoryblock.size = 5000
but this gives “NilObjectException”
Ouch!

Any ideas?

2

You have declared your memoryblock but have you created it yet?

3

Thanks, Kevin.

When I tried
Var mymemoryblock as new memoryblock (5000)
Xojo created a new local memory block, so how do I create the global one?

4

Var declares a local variable. Since you have already declared your global property you can just do:

mymemoryblock as new memoryblock (5000)

5

I think you mean:

mymemoryblock = new MemoryBlock( 5000 )
6

I did.

7

if mymemoryblock is a global variable,

You might initialise it in app.open using

mymemoryblock = new MemoryBlock( 26000 )
and then use it.

Later, if you want a smaller one and don’t care about the content, you can do this somewhere else:

mymemoryblock = new MemoryBlock( 5000 )

but if you want the memoryblock to change size and keep the contents that’s when you
can try using .size

mymemoryblock.size = 5000

If the new size is bigger than the old, it should contain the same data (Xojo will have done this by allocating new memory and copying A to B
Not sure what they do for a smaller one, but in both cases you should not (IMO) rely on anything that stored the address in memory of the memoryblock before the resize.

8

Pretty sure it’s truncated.

9

Thanks, Kevin, Kem and Jeff.
mymemoryblock = new MemoryBlock( 5000 )
works! I would never have guessed this from my reading of the Xojo documentation. Perhaps Xojo should change the documentation into a Wiki so that useful information can be added to it (and obsolete information removed) by Xojo users.

10

Considering they changed away from that over the last few years, I doubt it.