Hi Wei, > --- /dev/null > +++ b/lib/newlib_tests/test_macros07.c nit: Instead of creating a new test I would add it to existing test_macros02.c (it would reduce some duplicity). Also having exp_errs_pass[] and exp_errs_fail[] static and put testing all 4 macros into it's own functions, I'll send a suggestion shortly. Kind regards, Petr