---
source: tests/output.rs
expression: "get_stdout(&[item])"
---
anyhow                                  Macro anyhow::ensure                               rusty-man

SYNOPSIS
      macro_rules! ensure {
          ($cond:expr, $msg:literal $(,)?) => { ... };
          ($cond:expr, $err:expr $(,)?) => { ... };
          ($cond:expr, $fmt:expr, $($arg:tt)*) => { ... };
      }

DESCRIPTION
      Return early with an error if a condition is not satisfied.
      
      This macro is equivalent to `if !$cond { return Err(From::from($err)); }`.
      
      Analogously to `assert!`, `ensure!` takes a condition and exits the function if the condition
      fails. Unlike `assert!`, `ensure!` returns an `Error` rather than panicking.
      
      # Example
      
      ensure!(user == 0, "only user 0 is allowed");
      #[derive(Error, Debug)]
      enum ScienceError {
          #[error("recursion limit exceeded")]
          RecursionLimitExceeded,
          ...
      }
      ensure!(depth <= MAX_DEPTH, ScienceError::RecursionLimitExceeded);