const print = @import("std").debug.print; pub fn main() void { const result = getNumberOrFail(); if (result) |number| { print("got number: {}\n", .{number}); } else |err| { print("got error: {s}\n", .{@errorName(err)}); } } fn getNumberOrFail() !i32 { return error.UnableToReturnNumber; } // exe=succeed