macro_rules! anyhow { ($msg:literal $(,)?) => { ... }; ($err:expr $(,)?) => { ... }; ($fmt:expr, $($arg:tt)*) => { ... }; }
Expand description
Construct an ad-hoc error from a string or existing non-anyhow
error
value.
This evaluates to an Error
. It can take either just a
string, or a format string with arguments. It also can take any custom type
which implements Debug
and Display
.
If called with a single argument whose type implements std::error::Error
(in addition to Debug
and Display
, which are always required), then that
Error impl’s source
is preserved as the source
of the resulting
anyhow::Error
.
§Example
use anyhow::{anyhow, Result};
fn lookup(key: &str) -> Result<V> {
if key.len() != 16 {
return Err(anyhow!("key length must be 16 characters, got {:?}", key));
}
// ...
}