null_ptr          131 maint/gnulib/tests/test-canonicalize-lgpl.c     result = canonicalize_file_name (null_ptr ());
null_ptr          135 maint/gnulib/tests/test-canonicalize.c     result1 = canonicalize_file_name (null_ptr ());
null_ptr          100 maint/gnulib/tests/test-ptsname_r.c   result = ptsname_r (fd, null_ptr (), 0);