GIO is a library, designed to present programmers with a modern and usable interface to a virtual file system. It allows applications to access local and remote files with a single consistent API, which was designed "to overcome the shortcomings of GnomeVFS" and be "so good that developers prefer it over raw POSIX calls."
The abstract file system model of GIO consists of a number of interfaces and base classes for I/O and files.
There is a number of stream classes, similar to the input and output stream hierarchies that can be found in frameworks like Java.
There are interfaces related to applications and the types of files they handle.
There is a framework for storing and retrieving application settings.
There is support for network programming, including name resolution, lowlevel socket APIs and highlevel client and server helper classes.
There is support for connecting to D-Bus, sending and receiving messages, owning and watching bus names, and making objects available on the bus.
Beyond these, GIO provides facilities for file monitoring, asynchronous I/O and filename completion. In addition to the interfaces, GIO provides implementations for the local case. Implementations for various network file systems are provided by the GVfs package as loadable modules.