CODEWITHSUNDEEP
delphi
mcmar
mcmar

Reputation: 450

Why am I getting a 217 error when I call this finalization section?

I'm getting a runtime 217 error that I've tracked down to the finalization section of one of my units. This is the code :

finalization
begin
  for I:= 0 to CacheList.Count - 1 do
  begin
    tempRecord := CacheList.Items[I];
    for k := 0 to length(tempRecord.details) - 1 do
    begin
      tempRecord.Details[k].free;
    end;
    tempRecord.free;
  end;
  CacheList.Free;
end;

and tempRecord is :

Record = class
 Details : array of CachedDetails;
 key : string;
end;

CachedDetails = class
 EDate : TDateTime;
 A     : Real;
 B     : Real;
 C     : Real;
end;

Even though I get the error, the process does completely successfully. And if I simply comment out the entire finalization the error goes away, but I obviously don't want to leak memory. Am I improperly calling the frees?

Upvotes: 1

Views: 423

Answers (1)

Sir Rufo
Sir Rufo

Reputation: 19096

It is not a good advice to Free Items of a List, while they belong to the list. You have to check if it is a kind of TObjectList and if this List owns the objects.

Or you Extract the Item from List and free it.

finalization
begin
  while CacheList.Count > 0 do
  begin
    tempRecord := CacheList.Extract( CacheList.First );
    for k := 0 to length(tempRecord.details) - 1 do
    begin
      tempRecord.Details[k].free;
    end;
    tempRecord.free;
  end;
  CacheList.Free;
end;

But just as a think it over, if you hand over the destroy responsibility to the Record class and CacheList a TObjectList with OwnsObjects=True then your finlization code will look like this

finalization

CacheList.Free;

Upvotes: 1

Related Questions