Subroutine C-47 was one of the computer core's subroutines aboard the USS Enterprise-D. It controlled library computer access, replicator selection, and recreational programming. These were not considered by Chief Engineer Geordi La Forge as critical systems.
In 2369, subroutine C-47 was replaced by elements of Data's personal programming during an interface experiment, conducted with Geordi La Forge. This caused malfunctions throughout the ship, affecting replicators, music selections, holodeck programs, and Beverly Crusher 's script, "Something for Breakfast". (TNG: "A Fistful of Datas")