[Lazarus] Unicode branch

[Hans-Peter Diettrich]

Marco van de Voort schrieb:
> On Sat, Jun 29, 2013 at 08:47:37PM -0400, waldo kitty wrote:
>>> (Some versions of?) Delphi deallocate interfaces at the end of a block of
>>> procedures, not immediately after first usage.
>> first usage or last usage?
> 
> Last usage of course, sorry.

I'm somewhat confused now. When an object has an definite "last use", it 
should not matter when it is destroyed afterwards, sooner or later.

A problem I could imagine were a refcount dropping to zero *before* that 
reference is stored in another variable. E.g. in
   intfvar := intfvar;
it will be a bad idea to _Release the old reference stored in the 
intfvar variable while the same reference is kept in a register or 
stack, before assigning the new reference to the variable. This is a 
known aliasing problem, which must be solved properly by every compiler. 
I'd solve it this way (compiled code):
//tempvar added by the compiler
   tempvar := intfvar; //intfvar.AddRef
   intfvar := newvalue; //intfvar._Release; newvalue.AddRef;
   tempvar := nil; //here or on exit from the subroutine or code block
Another solution could use the property setter pattern:
   if value <> newvalue then value := newvalue;

DoDi