Extending operating system subsystems

A method performed by a computer system for extending an application program interface of a subsystem of an operating system, the subsystem of the operating system having a set of locations associated with functions of the application program interface, the method comprising:

• receiving a library that provides functions for extending the application program interface of the subsystem of the operating system;
• adding dynamically a set of locations corresponding to functions provided by the library;
• providing a known local procedure call port, the known local procedure call port for receiving requests to identify a dynamically added location from the set of dynamically added locations;
• receiving a request to identify a dynamically added location corresponding to a function, the request to identify a dynamically added location received at the known local procedure call port and indicating the function;
• determining a dynamically added location corresponding to the function indicated in the request to identify a dynamically added location;
• providing the determined dynamically added location;
• receiving a request to perform an action, the action generally associated with the subsystem of the operating system, the action received at the provided dynamically added location;
• and
• invoking the function of the library corresponding to the action.

A computer-readable medium having computer-executable instructions for extending a subsystem of an operating system, the subsystem of the operating system having an application program interface, the method comprising:

• receiving a library that provides functions for extending the application program interface of the subsystem of the operating system;
• adding dynamically a set of locations corresponding to functions provided by the library;
• providing a known local procedure call port, the known procedure call port for receiving requests to identify a dynamically added location from the set of dynamically added locations;
• and
• receiving a request to identify a dynamically added location corresponding to a function, the request to identify a dynamically added location received at the known local procedure call port and indicating the function.