Macro v9::prelude_lib::panic 1.0.0[−][src]
Panics the current thread.
This allows a program to terminate immediately and provide feedback
to the caller of the program. panic!
should be used when a program reaches
an unrecoverable state.
This macro is the perfect way to assert conditions in example code and in
tests. panic!
is closely tied with the unwrap
method of both
Option
and Result
enums. Both implementations call
panic!
when they are set to None
or Err
variants.
This macro is used to inject panic into a Rust thread, causing the thread to
panic entirely. This macro panics with a string and uses the format!
syntax
for building the message.
Each thread’s panic can be reaped as the Box
<
Any
>
type,
which contains either a &str
or String
for regular panic!()
invocations.
To panic with a value of another other type, panic_any
can be used.
Result
enum is often a better solution for recovering from errors than
using the panic!
macro. This macro should be used to avoid proceeding using
incorrect values, such as from external sources. Detailed information about
error handling is found in the book.
See also the macro compile_error!
, for raising errors during compilation.
Current implementation
If the main thread panics it will terminate all your threads and end your
program with code 101
.
Examples
panic!(); panic!("this is a terrible mistake!"); panic!("this is a {} {message}", "fancy", message = "message"); std::panic::panic_any(4); // panic with the value of 4 to be collected elsewhere