error: function is never used: `temporary_cstring` --> $DIR/cstring.rs:4:1 | 4 | fn temporary_cstring() { | ^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D dead-code` implied by `-D warnings` error: you are getting the inner pointer of a temporary `CString` --> $DIR/cstring.rs:7:5 | 7 | CString::new("foo").unwrap().as_ptr(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D temporary-cstring-as-ptr` implied by `-D warnings` = note: that pointer will be invalid outside this expression help: assign the `CString` to a variable to extend its lifetime --> $DIR/cstring.rs:7:5 | 7 | CString::new("foo").unwrap().as_ptr(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^