Judging by the documentation, if you issue a PRAGMA foreign_keys; and no row is returned containing a 0 or 1, then you are using an unsupported version of SQLite, or the library was compiled with foreign key support disabled. I am struggling to find any documentation that states if anything will occur if enabling foreign keys in the connection string, when the version does not support foreign keys.
Judging by the documentation, if you issue a PRAGMA foreign_keys; and no row is returned containing a 0 or 1, then you are using an unsupported version of SQLite, or the library was compiled with foreign key support disabled. I am struggling to find any documentation that states if anything will occur if enabling foreign keys in the connection string, when the version does not support foreign keys.