Handling unhandled errors better.

Now the Unhandled error contains the errno value for reference.

src/c/errno.rs

@@ -43,6 +43,9 @@ pub enum CError
    /// There was a detected error, but it
    /// is not one handled by CError.
    Unhandled
+   {
+      errno: i32
+   }
 }
 
 
@@ -53,11 +56,18 @@ impl CError
    pub fn is_handled_error(errno: i32) -> bool
    {
       let error: CError;
+      let unhandled: CError;
+
+      // Create an error that would be if this was unhandled.
+      unhandled = CError::Unhandled
+                  {
+                     errno: errno
+                  };
 
       // Turn the error value into a CError and
       // check if it is an Unhandled error.
       error = CError::from(errno);
-      if error != CError::Unhandled
+      if error != unhandled
       {
          true
       }
@@ -76,7 +86,7 @@ impl CError
    /// Set the current Error for the system.
    pub fn set_current_error(error: CError)
    {
-      set_errno(error as i32);
+      set_errno(error.into());
    }
 
    /// Clear the current Error.
@@ -113,7 +123,22 @@ impl From<i32> for CError
          EDOM => { CError::Domain }
          ERANGE => { CError::Range }
          EILSEQ => { CError::IllegalSequence }
-         _ => { CError::Unhandled }
+         _ => { CError::Unhandled { errno: val } }
+      }
+   }
+}
+
+impl Into<i32> for CError
+{
+   fn into(self) -> i32
+   {
+      match self
+      {
+         CError::None => { NO_ERROR }
+         CError::Domain => { EDOM }
+         CError::Range => { ERANGE }
+         CError::IllegalSequence => { EILSEQ }
+         CError::Unhandled { errno: val } => { val }
       }
    }
 }
@@ -128,7 +153,8 @@ impl Error for CError
          CError::Domain => { "Math argument out of domain of function" }
          CError::Range => { "Math result not representable" }
          CError::IllegalSequence => { "Illegal byte sequence" }
-         CError::Unhandled => { "Detected an Error not handled by CError" }
+         CError::Unhandled { errno: _val } =>
+            { "Detected an Error not handled by CError" }
       }
    }