EBackend.Cache.foreach_update

### Method

# EBackend Cacheforeach_update

since: 3.26

#### Declaration [src]

    gboolean
    e_cache_foreach_update (
      ECache* cache,
      ECacheDeletedFlag deleted_flag,
      const gchar* where_clause,
      ECacheUpdateFunc func,
      gpointer user_data,
      GCancellable* cancellable,
      GError** error
    )

#### Description [src]

Calls `func` for each found object, which satisfies the criteria for both `deleted_flag` and `where_clause`, letting the caller update values where necessary. The return value of `func` is used to determine whether the call was successful, not whether there are any changes to be saved. If anything fails during the call then the all changes are reverted.

When there are requested any changes by the `func`, this function also calls `e_cache_copy_missing_to_column_values()` to ensure no descendant column data is lost.

Available since: 3.26

#### Parameters

`deleted_flag`

  Type: `ECacheDeletedFlag`

  One of `ECacheDeletedFlag` enum.

`where_clause`

  Type: `const gchar*`

  An optional SQLite WHERE clause part, or `NULL`.

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

`func`

  Type: `ECacheUpdateFunc`

  An `ECacheUpdateFunc` function to call for each object.

`user_data`

  Type: `gpointer`

  User data for the `func`.

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

`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.