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
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