What is the alternative to FreeAndNil in Delphi 7?
delphi, delphi-7
Solution
Strictly speaking, to dispose of an object you only need to call `Destroy`. However, if the reference is `nil`, ie. has not been assigned a pointer to a valid instance of an object, this would cause an access violation, so it's recommended to call `Free` instead which checks first if the passed reference is nil and does nothing in that case. `FreeAndNil` first assigns the passed reference to a temporary local variable, then assigns `nil` to the passed reference, then calls `Free` to dispose of the instance. The only difference between `FreeAndNil` and your sequence `obj.Free; obj := nil;` is that in the first case the passed reference will be `nil` even if the destructor raises an exception.
Problem
I have a doubt that whether FreeAndNil is the ideal approach to dispose an object . I have come across codes where something like ``` StringList1.Free; StringList1 := Nil; ``` is used. Is the above line an overkill , or is it a better way to do things ? What is the difference between the two approaches?