Hi
I checkout fpc trunk and try to build it but fpmake raise access violation exception
how to solve it ?

./fpmake compile --localunitdir=.. --os=linux --cpu=x86_64 -o -Ur -o -Xs -o -O2 -o -n -o -Cg -o -dx86_64 -o -dRELEASE
--compiler=/home/mohsen/Applications/Lazarus/fpc-trunk/compiler/ppcx64 -bu -o -XX -o -CX
The installer encountered the following error:
Access violation

Same here when building fpc-arm an a mac with fpc 2.6.4

Von meinem iPad gesendet

It's because of r32327. Michael?

Jonas

Strange, I created a test before committing, and it ran fine. Well. I reinstated line 1132. But according to logic, that line should not be necessary. Maybe I am not properly seeing a case where it can go wrong.

Michael.

Hi,

Michael Van Canneyt wrote

Strange, I created a test before committing, and it ran fine. Well. I reinstated line 1132. But according to logic, that line should not be necessary. Maybe I am not properly seeing a case where it can go wrong.

Wild try/guess just by looking at the code:

If FList^[Index].FString is not nil (which is true after the System.Move() there), then at the next line at the assignment, there will be an attempt to reduce the reference count of the string before assigning the new one, and then it's a very likely case that the reference count of it will be zero, so the string is freed.

Which means the string at FList^[Index+1] will be invalid, because System.Move() doesn't do anything with the reference counts, so at that point FList^[Index] and FList^[Index+1] are eachothers clones, but the reference count doesn't reflect that.

Therefore that nil (and the pointer cast!) is very much required. The pointer cast is needed, so the string will be handled as pointer, and only the value is erased, but the refrence counts are untouched.

Someone please fix me if I'm wrong. :)

Charlie

Works again for me, thank you for fixing!

Michael

But the fillword should have cleared all allocated memory in SetCapacity ? So how can it be that there is a (valid) index where FList^[Index].FString is not nil ?

Wait, I think I have it.
When a delete is done, a move happens, but the item at Flist[Count] is not cleared.

Probably that is what causes this.

Michael.