*
* 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) (num) & (1 << 30)? \
+ strerror((num) & ((1 << 30) - 1)) : \
+ para_errlist[ERRNUM_TO_SS(num)] [ERRNUM_TO_INDEX(num)]
+
+#define ERRNO_TO_PARA_ERROR(num) (-((num) | (1 << 30)))
/**
* define the error list for one subsystem