[Rust Guide] 9.3. Result Enum and Recoverable Errors Pt. 2 - Error Propagation, Question Mark Operator, and Chained Call

If you find this helpful, please like, bookmark, and follow. To keep learning along, follow this series. 9.3.1 Propagating Errors When a function you write contains calls that may fail, you can either handle the error inside the function or return the error to the caller and let the caller decide how to handle it. Take a look at an example: use std :: fs :: File ; use std :: io ::{ self , Read }; fn read_username_from_file () -> Result String , io :: Error > { let f = File :: open ( "6657.txt" )