Menu
TObject.InstanceSize returns 8, yet TObject doesn't declare any data members. According to the implementation of TObject.ClassType, the first 4 bytes can be explained as a pointer to the object's TClass metadata. Anyone know what the other 4 bytes of overhead are there for?
EDIT: Apparently this is specific to D2009. In older versions, it's only 4 bytes.
720
A data object is a region of storage that contains a value or group of values. Each value can be accessed using its identifier or a more complex expression that refers to the object. In addition, each object has a unique data type.
Data object is usually represented as storage in Computer memory and a data value is represented by a pattern of bits.
Data object is a general term for a region of data storage that can be used to hold values. The C standard uses just the term object for this concept. One way to identify an object is by using the name of a variable.
In Delphi 2009, there is the ability to have a reference to a synchronization monitor. See:
class function TMonitor.GetFieldAddress(AObject: TObject): PPMonitor;
class function TMonitor.GetMonitor(AObject: TObject): PMonitor;
...in System.pas
Also, there is still a pointer to the VMT. (Virtual Method Table.) From Delphi in a Nutshell:
The TObject class declares several methods and one special, hidden field to store a reference to the object's class. This hidden field points to the class's virtual method table (VMT). Every class has a unique VMT and all objects of that class share the class's VMT.
134
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
