As I understand it, garbage collection only takes place when all references to the "garbage" are removed.

A daemon generally has to fork or something similar to handle new requests and this tends to ensure termination rather than collection.

Otherwise declare request structures at a higher scope than the request servicing routines and simply remove them on completion - any working references at a lower level will not then prevent garbage collection.

Update: alternatively, even easier: declare within the scope of the service routine and return blanco or only a status code to the higher scope on completion - no references will out-survive the handling in that case.