README.Coding: Approve DBG statements using dom_sid_str_buf

Signed-off-by: Volker Lendecke <[email protected]>
Reviewed-by: Ralph Boehme <[email protected]>

README.Coding

@@ -432,6 +432,22 @@ an iterator style:
 		   ... do something with opt ...
 	}
 
+Another exception: DBG messages for example printing a SID or a GUID:
+Here we don't expect any surprise from the printing functions, and the
+main reason of this guideline is to make debugging easier. That reason
+rarely exists for this particular use case, and we gain some
+efficiency because the DBG_ macros don't evaluate their arguments if
+the debuglevel is not high enough.
+
+	if (!NT_STATUS_IS_OK(status)) {
+		struct dom_sid_buf sid_buf;
+		struct GUID_txt_buf guid_buf;
+		DBG_WARNING(
+		    "objectSID [%s] for GUID [%s] invalid\n",
+		    dom_sid_str_buf(objectsid, &sid_buf),
+		    GUID_buf_string(&cache->entries[idx], &guid_buf));
+	}
+
 But in general, please try to avoid this pattern.