*/
#define ERRNUM_TO_INDEX(num) (((1 << SS_SHIFT) - 1) & (num))
+#define SYSTEM_ERROR_BIT 30
+
+#define IS_SYSTEM_ERROR(num) (!!((num) & (1 << SYSTEM_ERROR_BIT)))
+
+#define ERRNO_TO_PARA_ERROR(num) ((num) | (1 << SYSTEM_ERROR_BIT))
+
+#define IS_SYSTEM_ERRNO(val, _errno) (ERRNO_TO_PARA_ERROR(_errno) == (val))
+
/**
* paraslash's version of strerror(3)
*
* expands to the error text of \a num (a string constant).
*/
-#define PARA_STRERROR(num) para_errlist[ERRNUM_TO_SS(num)] [ERRNUM_TO_INDEX(num)]
+#define PARA_STRERROR(num) IS_SYSTEM_ERROR(num)? \
+ strerror((num) & ((1 << SYSTEM_ERROR_BIT) - 1)) : \
+ para_errlist[ERRNUM_TO_SS(num)] [ERRNUM_TO_INDEX(num)]
/**
* define the error list for one subsystem