MySQL 5.6 OS X 10.8: how tell if my.cnf read?

Question

With mysqld running, I expect to see that /etc/my.cnf has been used by at least one of the commands

ps aux | grep mysql | grep -v grep

mysqladmin variables | grep defaults-file

showing the value of --defaults-file. But I see no such item. Why not?

I think /etc/my.cnf is being read, since if I put an erroneous entry in its [mysqld] section, e.g., error = true then when I try to start mysqld it aborts with an ERROR message.

I'm using the installation by running mysql-5.6.10-osx10.7-x86_64.pkg from mysql-5.6.10-osx10.7-x86_64.dmg.