EDataBook.BookMetaBackend.get_changes_sync

### Method

# EDataBook BookMetaBackendget_changes_sync

since: 3.26

#### Declaration [src]

    gboolean
    e_book_meta_backend_get_changes_sync (
      EBookMetaBackend* meta_backend,
      const gchar* last_sync_tag,
      gboolean is_repeat,
      gchar** out_new_sync_tag,
      gboolean* out_repeat,
      GSList** out_created_objects,
      GSList** out_modified_objects,
      GSList** out_removed_objects,
      GCancellable* cancellable,
      GError** error
    )

#### Description [src]

Gathers the changes since the last check which had been done on the remote side.

The `last_sync_tag` can be used as a tag of the last check. This can be `NULL`, when there was no previous call or when the descendant doesn’t store any such tags. The `out_new_sync_tag` can be populated with a value to be stored and used the next time.

The `out_repeat` can be set to `TRUE` when the descendant didn’t finish read of all the changes. In that case the `meta_backend` calls this function again with the `out_new_sync_tag` as the `last_sync_tag`, but also notifies about the found changes immediately. The `is_repeat` is set to `TRUE` as well in this case, otherwise it’s `FALSE`.

The descendant can populate also EBookMetaBackendInfo::object of the `out_created_objects` and `out_modified_objects`, if known, in which case this will be used instead of loading it with e_book_meta_backend_load_contact_sync().

It is optional to implement this virtual method by the descendant. The default implementation calls `e_book_meta_backend_list_existing_sync()` and then compares the list with the current content of the local cache and populates the respective lists appropriately.

Each output `GSList` should be freed with g_slist_free_full (objects, e_book_meta_backend_info_free); when no longer needed.

Available since: 3.26

#### Parameters

`last_sync_tag`

  Type: `const gchar*`

  Optional sync tag from the last check.

  The argument can be `NULL`.
  The data is owned by the caller of the method.
  The value is a NUL terminated UTF-8 string.

`is_repeat`

  Type: `gboolean`

  Set to `TRUE` when this is the repeated call.

`out_new_sync_tag`

  Type: `gchar**`

  New sync tag to store on success.

  The argument will be set by the function.
  The caller of the method takes ownership of the returned data, and is responsible for freeing it.
  The value is a NUL terminated UTF-8 string.

`out_repeat`

  Type: `gboolean*`

  Whether to repeat this call again; default is `FALSE`.

  The argument will be set by the function.

`out_created_objects`

  Type: A list of `None`

  a `GSList` of `EBookMetaBackendInfo` object infos which had been created since the last check.

  The argument will be set by the function.
  The caller of the method takes ownership of the returned data, and is responsible for freeing it.

`out_modified_objects`

  Type: A list of `None`

  a `GSList` of `EBookMetaBackendInfo` object infos which had been modified since the last check.

  The argument will be set by the function.
  The caller of the method takes ownership of the returned data, and is responsible for freeing it.

`out_removed_objects`

  Type: A list of `None`

  a `GSList` of `EBookMetaBackendInfo` object infos which had been removed since the last check.

  The argument will be set by the function.
  The caller of the method takes ownership of the returned data, and is responsible for freeing it.

`cancellable`

  Type: `GCancellable`

  Optional `GCancellable` object, or `NULL`.

  The argument can be `NULL`.
  The data is owned by the caller of the method.

`error`

  Type: `GError **`

  The return location for a recoverable error.

  The argument can be `NULL`.
  If the return location is not `NULL`, then you must initialize it to a `NULL` `GError*`.
  The argument will be left initialized to `NULL` by the method if there are no errors.
  In case of error, the argument will be set to a newly allocated `GError`; the caller will take ownership of the data, and be responsible for freeing it.

#### Return value

Type: `gboolean`

Whether succeeded.