int sqlite3_snapshot_get( sqlite3 *db, const char *zSchema, sqlite3_snapshot **ppSnapshot );
The sqlite3_snapshot_get(D,S,P) interface attempts to make a new sqlite3_snapshot object that records the current state of schema S in database connection D. On success, the sqlite3_snapshot_get(D,S,P) interface writes a pointer to the newly created sqlite3_snapshot object into *P and returns SQLITE_OK. If there is not already a read-transaction open on schema S when this function is called, one is opened automatically.
The following must be true for this function to succeed. If any of the following statements are false when sqlite3_snapshot_get() is called, SQLITE_ERROR is returned. The final value of *P is undefined in this case.
This function may also return SQLITE_NOMEM. If it is called with the database handle in autocommit mode but fails for some other reason, whether or not a read transaction is opened on schema S is undefined.
SQLite is in the Public Domain.