Service_USB 0 - Pipe released — Indicate pipe release
| R0 | 0 (reason code) |
| R1 | &80C00 (USB Service call) |
| R2 | Pointer to controller structure |
| R3 | Pointer to device structure |
| R4 | Pointer to endpoint structure |
| R5 | Number of remaining applications sharing the pipe |
| R0 | preserved |
| R1 | preserved to pass on (do not claim) |
| R2, R3, R4, R5 | preserved |
This service call is generated when a pipe is closed (Shared pipes will generate a service call for each claimants closure). Can be used by programs waiting for exclusive pipe access. The endpoint structure is passed to enable identification of pipes available for re-use.