Represent the errno as a i32

Author: Erk-

src/linux.rs

@@ -33,24 +33,20 @@ pub struct LinuxI2CBus {
     devfile: File,
 }
 
-/// Linux Errno error.
-#[derive(Debug)]
-pub struct Errno {
-    nix: nix::Error,
-}
-
 /// Linux I2C errors
 #[derive(Debug)]
 pub enum LinuxI2CError {
-    /// OS error
-    Errno(Errno),
+    /// Errno from a failing libc call. Sourced  from `nix`.
+    ///
+    /// To interpret this value `nix::Error::from_i32` should be used.
+    Errno(i32),
     /// Input/output error
     Io(io::Error),
 }
 
 impl From<nix::Error> for LinuxI2CError {
     fn from(e: nix::Error) -> Self {
-        LinuxI2CError::Errno(Errno { nix: e })
+        LinuxI2CError::Errno(e as i32)
     }
 }
 
@@ -64,15 +60,18 @@ impl From<LinuxI2CError> for io::Error {
     fn from(e: LinuxI2CError) -> io::Error {
         match e {
             LinuxI2CError::Io(e) => e,
-            LinuxI2CError::Errno(e) => e.nix.into(),
+            LinuxI2CError::Errno(e) => io::Error::from_raw_os_error(e),
         }
     }
 }
 
 impl fmt::Display for LinuxI2CError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
-            LinuxI2CError::Errno(ref e) => fmt::Display::fmt(&e.nix, f),
+            LinuxI2CError::Errno(e) => {
+		let error = nix::Error::from_i32(e);
+		fmt::Display::fmt(&error, f)
+	    },
             LinuxI2CError::Io(ref e) => fmt::Display::fmt(e, f),
         }
     }
@@ -82,7 +81,7 @@ impl Error for LinuxI2CError {
     fn cause(&self) -> Option<&dyn Error> {
         match *self {
             LinuxI2CError::Io(ref e) => Some(e),
-            LinuxI2CError::Errno(ref e) => Some(&e.nix),
+            LinuxI2CError::Errno(_) => None,
         }
     }
 }