gnu Smalltalk provides methods to query its own internal data structures.
You may determine the real memory address of an object or the real
memory address of the OOP table that points to a given object, by
using messages to the
Memory class, described below.
Returns the index of the OOP for anObject. This index is immume from garbage collection and is the same value used by default as an hash value for anObject (it is returned by Object's implementation of
Converts the given OOP index (not address) back to an object. Fails if no object is associated to the given index.
Converts the given OOP index (not address) back to an object. Returns nil if no object is associated to the given index.
Other methods in ByteArray and Memory allow to read various C types
ucharAt:, etc.). For examples of using
asObject, look at the Blox source code in
Another interesting class is ObjectMemory. This provides a few methods that enable one to tune the virtual machine's usage of memory; many methods that in the past were instance methods of Smalltalk or class methods of Memory are now class methods of ObjectMemory. In addition, and that's what the rest of this section is about, the virtual machines signals events to its dependents exactly through this class.
The events that can be received are
ObjectMemory quitwas sent or because the specified files were all filed in. Exiting from within this event might cause an infinite loop, so be careful.