SQLITE_ACCESS_EXISTS,
  SQLITE_ACCESS_READWRITE,
  SQLITE_ACCESS_READ —
Flags for the xAccess VFS method
#define SQLITE_ACCESS_EXISTS
#define SQLITE_ACCESS_READWRITE
#define SQLITE_ACCESS_READ
These integer constants can be used as the third parameter to the xAccess method
  of an sqlite3_vfs object. They determine what kind of permissions the xAccess
  method is looking for. With SQLITE_ACCESS_EXISTS, the xAccess method simply
  checks whether the file exists. With SQLITE_ACCESS_READWRITE, the xAccess
  method checks whether the named directory is both readable and writable (in
  other words, if files can be added, removed, and renamed within the
  directory). The SQLITE_ACCESS_READWRITE constant is currently used only by the
  temp_store_directory pragma, though this could change in a future release of
  SQLite. With SQLITE_ACCESS_READ, the xAccess method checks whether the file is
  readable. The SQLITE_ACCESS_READ constant is currently unused, though it might
  be used in a future release of SQLite.