+
+(define-alien-routine ("os_get_errno" get-errno) integer)
+(setf (fdocumentation 'get-errno 'function)
+ "Return the value of the C library pseudo-variable named \"errno\".")
+
+;;; Decode errno into a string.
+(defun strerror (&optional (errno (get-errno)))
+ (alien-funcall (extern-alien "strerror" (function c-string int)) errno))