stdio: nicer error handling

safe_libc/src/stdio.rs

@@ -7,6 +7,12 @@ pub struct Error {
 	pub errno: errno::Errno,
 }
 
+impl From<Error> for fmt::Error {
+	fn from(_err: Error) -> fmt::Error {
+		fmt::Error
+	}
+}
+
 pub type Result<T> = core::result::Result<T, Error>;
 
 #[inline]
@@ -58,9 +64,7 @@ impl BasicOStream {
 impl fmt::Write for BasicOStream {
 	#[inline]
 	fn write_str(&mut self, s: &str) -> fmt::Result {
-		if self.write(s.as_bytes()).is_err() {
-			return Err(fmt::Error);
-		}
+		self.write(s.as_bytes())?;
 		Ok(())
 	}
 }