SQLite since version 3.7.7 supports URI Filenames. This allows more flexibility in connection with in memory databases, like having multiple in memory databases.

In order to enable this there are three possibilities:

1. Set SQLITE_USE_URI=1 on SQLite compile time
2. Set sqlite3_config(SQLITE_CONFIG_URI,1) on sqlite setup (before sqlite3_initialize())
3. Use sqlite3_open_v2() with SQLITE_USE_URI

I think in the Poco case it would be best to use method 2 and globally support URI filenames by default.