While debugging #741, I noticed that your eosio-cpp driver uses a temporary file in /tmp that's created ad-hoc by concatenating "/tmp" and the file name, e.g. /tmp/addressbook_with_age_and_notify.cpp.o when compiling addressbook_with_age_and_notify.cpp in a directory.

See here for the code that does this.

The above would make sense only in a single-user, single-process environment, otherwise it opens up the potential for conflicts or even TOCTOU attacks.