3. Features of GNU Smalltalk

In this section, the features which are specific to GNU Smalltalk are described. These features include support for calling C functions from within Smalltalk, accessing environment variables, and controlling various aspects of compilation and execution monitoring.

Note that, in general, GNU Smalltalk is much more powerful than the original Smalltalk-80, as it contains a lot of methods that are common in today's Smalltalk implementation and are present in the ANSI Standard for Smalltalk, but were absent in the Blue Book. Examples include Collection's allSatisfy: and anySatisfy: methods and many methods in SystemDictionary (the Smalltalk dictionary's class).

3.1 Memory accessing methods		The direct memory accessing classes and methods, plus broadcasts from the virtual machine.
3.2 Namespaces		Avoiding clashes between class names.
3.3 Disk file-IO primitive messages		Methods for reading and writing disk files.
3.4 The GNU Smalltalk ObjectDumper		Methods that read and write objects in binary format.
3.5 Special kinds of object		Methods to assign particular properties to objects.
3.6 The context unwinding system		A way to protect execution of blocks from exceptions.
3.7 Packages		An easy way to install Smalltalk code into an image.