Function macro_state::proc_has_state
source · [−]Expand description
An analogue for has_state!
that should only be used within proc macros.
Checks if an existing state value can be found for the specified key
.
Note that this function is infallible – it should never panic and will always return
true
or false
.
Example
use macro_state::*;
proc_write_state("my key", "hey").unwrap();
assert_eq!(proc_has_state("my key"), true);
assert_eq!(proc_has_state("unknown key"), false);
Internally this function simply calls proc_read_state
, returning false
in the event
of an IO error.