use std::borrow::Cow::{Borrowed, Owned}; use std::ffi::CStr; use std::os::raw::c_char; #[test] fn to_str() { let data = b"123\xE2\x80\xA6\0"; let ptr = data.as_ptr() as *const c_char; unsafe { assert_eq!(CStr::from_ptr(ptr).to_str(), Ok("123…")); assert_eq!(CStr::from_ptr(ptr).to_string_lossy(), Borrowed("123…")); } let data = b"123\xE2\0"; let ptr = data.as_ptr() as *const c_char; unsafe { assert!(CStr::from_ptr(ptr).to_str().is_err()); assert_eq!(CStr::from_ptr(ptr).to_string_lossy(), Owned::(format!("123\u{FFFD}"))); } }