std::assert!
[−]
macro_rules! assert { ( $ cond : expr ) => { ... }; ( $ cond : expr , $ ( $ arg : tt ) + ) => { ... }; }
Ensure that a boolean expression is true
at runtime.
This will invoke the panic!
macro if the provided expression cannot be
evaluated to true
at runtime.
This macro has a second version, where a custom panic message can be provided.
Examples
// the panic message for these assertions is the stringified value of the // expression given. assert!(true); fn some_computation() -> bool { true } // a very simple function assert!(some_computation()); // assert with a custom message let x = true; assert!(x, "x wasn't true!"); let a = 3; let b = 27; assert!(a + b == 30, "a = {}, b = {}", a, b);