How to open a shared, in-memory database? about rusqlite HOT 1 CLOSED

This is a little tricky for two reasons. From the docs on sqlite3_open_v2:

• You must always pass one of SQLITE_OPEN_READONLY, SQLITE_OPEN_READWRITE, or SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE as the flags to open (optionally with other bits or'd in). This is why you're getting API misuses - shared_cache / open_uri by themselves aren't allowed.

• For in-memory databases shared cache databases specifically:

  Beginning with SQLite version 3.7.13, shared cache can be used on in-memory databases, provided that the database is created using a URI filename. For backwards compatibility, shared cache is always disable for in-memory databases if the unadorned name ":memory:" is used to open the database.

Using open_in_memory_with_flags uses the unadorned name ":memory:", so adding a SQLITE_OPEN_SHARED_CACHE flag to that call will essentially be ignored by SQLite. This should work, however, assuming SQLite no older than 3.7.13:

Connection::open_with_flags("file::memory:?cache=shared", SQLITE_OPEN_URI | SQLITE_OPEN_READ_WRITE)

from rusqlite.