Skip to content
Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

? operator

Pass an error back to the caller, or keep the value and continue.

expr? yields the Ok/Some value or returns early from the function with the Err (converted with From) or None.

Loading interactive…

Examples

  • let text = fs::read_to_string(path)?; gives the file's text, or returns the io::Error from the current function.

See also

error propagation Result unwrap
Read the full section →