FreeMemory() dilema

PolyVector · Post by **PolyVector** » Thu Dec 09, 2004 6:24 pm

I'm writing a PureBasic JIT compiler (don't get your hopes up, i'm new to this sort of thing)
Well here's my problem... My program(and debugger) will randomly crash at this line:

Code: Select all

Procedure CompileJMP(Address.l,ToAddress.l)
  Protected Buffer.l
  If Address
    Buffer=AllocateMemory(5)
    ;/do stuff
    FreeMemory(Buffer);-<<<<<<<CRASHES HERE>>>>>>>
  EndIf
  ProcedureReturn 5
EndProcedure

If I don't free the buffer everything's fine (except the obvious memory leak)
I know that my Buffer is valid because of debugging... I simply can't figure out why it won't allow me to free it... Is this a PB bug? Are there any ways to avoid this crash? OnError hasn't been able to help me here either

Post by **Rings** » Thu Dec 09, 2004 6:46 pm

works with no problems here:

Code: Select all

Procedure CompileJMP(Address.l,ToAddress.l)
  Protected Buffer.l
  If Address
    Buffer=AllocateMemory(5)
    ;/do stuff
    FreeMemory(Buffer);-<<<<<<<CRASHES HERE>>>>>>>
  EndIf
  ProcedureReturn 5
EndProcedure 

Result=CompileJMP(1024,1023)
Debug Result

maybe using threads ?

PolyVector · Post by **PolyVector** » Thu Dec 09, 2004 6:59 pm

it only randomly crashes inside a much larger program... I don't know if it's a windows thing or pb...

dige · Post by **dige** » Fri Dec 10, 2004 9:24 am

Maybe that helps:

Code: Select all

Procedure CompileJMP(Address.l,ToAddress.l)
  Static Buffer.l
  If Address
    Buffer = ReAllocateMemory ( Buffer, 5 )
    ;/do stuff
  EndIf
  ProcedureReturn 5
EndProcedure

cya dige

gnozal · Post by **gnozal** » Fri Dec 10, 2004 10:23 am

Did you tried GlobalAlloc_()/GlobalFree_() ?
If it don't work either it's not a purebasic problem.

PolyVector · Post by **PolyVector** » Fri Dec 10, 2004 1:05 pm

Good Idea...

PolyVector · Post by **PolyVector** » Fri Dec 10, 2004 1:28 pm

Great!
If I replace GlobalAlloc_() and GlobalFree_() it fixes everything

Thanks for the advice gnozal

Maybe I should post this in the bugs section?... Although I can't get any small piece of source to demonstrait it...

Post by **Fred** » Wed Dec 15, 2004 10:48 am

It probably moves the problem in another place, as the Allocate/Free commands are mostly an HeapAlloc/HeapFree wrapper.

gnozal · Post by **gnozal** » Wed Dec 15, 2004 11:06 am

PolyVector wrote:Great!
If I replace GlobalAlloc_() and GlobalFree_() it fixes everything
Thanks for the advice gnozal

Fred may be right.
I had the same problem once and using GlobalAlloc_()/GlobalFree_() fixed it. I realized later that there was a bug in my code (I tried to work with a non existing listicon row if I remember correctly) but I don't know if there was a link between the two problems.