GLib.VariantDict
Description: Reference for GLib.VariantDict

### Struct

# GLibVariantDict

since: 2.40

#### Description [src]

    struct GVariantDict {
      /* No available fields */
    }

`GVariantDict` is a mutable interface to `GVariant` dictionaries.

It can be used for doing a sequence of dictionary lookups in an efficient way on an existing `GVariant` dictionary or it can be used to construct new dictionaries with a hashtable-like interface. It can also be used for taking existing dictionaries and modifying them in order to create new ones.

`GVariantDict` can only be used with `G_VARIANT_TYPE_VARDICT` dictionaries.

It is possible to use `GVariantDict` allocated on the stack or on the heap. When using a stack-allocated `GVariantDict`, you begin with a call to `g_variant_dict_init()` and free the resources with a call to g_variant_dict_clear().

Heap-allocated `GVariantDict` follows normal refcounting rules: you allocate it with `g_variant_dict_new()` and use `g_variant_dict_ref()` and g_variant_dict_unref().

`g_variant_dict_end()` is used to convert the `GVariantDict` back into a dictionary-type `GVariant`. When used with stack-allocated instances, this also implicitly frees all associated memory, but for heap-allocated instances, you must still call `g_variant_dict_unref()` afterwards.

You will typically want to use a heap-allocated `GVariantDict` when you expose it as part of an API. For most other uses, the stack-allocated form will be more convenient.

Consider the following two examples that do the same thing in each style: take an existing dictionary and look up the “count” uint32 key, adding 1 to it if it is found, or returning an error if the key is not found. Each returns the new dictionary as a floating `GVariant`.

## Using a stack-allocated GVariantDict

      GVariant *
      add_to_count (GVariant  *orig,
                    GError   **error)
      {
        GVariantDict dict;
        guint32 count;

        g_variant_dict_init (&dict, orig);
        if (!g_variant_dict_lookup (&dict, "count", "u", &count))
          {
            g_set_error (...);
            g_variant_dict_clear (&dict);
            return NULL;
          }

        g_variant_dict_insert (&dict, "count", "u", count + 1);

        return g_variant_dict_end (&dict);
      }

## Using heap-allocated GVariantDict

      GVariant *
      add_to_count (GVariant  *orig,
                    GError   **error)
      {
        GVariantDict *dict;
        GVariant *result;
        guint32 count;

        dict = g_variant_dict_new (orig);

        if (g_variant_dict_lookup (dict, "count", "u", &count))
          {
            g_variant_dict_insert (dict, "count", "u", count + 1);
            result = g_variant_dict_end (dict);
          }
        else
          {
            g_set_error (...);
            result = NULL;
          }

        g_variant_dict_unref (dict);

        return result;
      }

Available since: 2.40

#### Constructors

###### g_variant_dict_new

Allocates and initialises a new `GVariantDict`.

since: 2.40

#### Instance methods

###### g_variant_dict_clear

Releases all memory associated with a `GVariantDict` without freeing the `GVariantDict` structure itself.

since: 2.40

###### g_variant_dict_contains

Checks if `key` exists in `dict`.

since: 2.40

###### g_variant_dict_end

Returns the current value of `dict` as a `GVariant` of type `G_VARIANT_TYPE_VARDICT`, clearing it in the process.

since: 2.40

###### g_variant_dict_init

Initialises a `GVariantDict` structure.

since: 2.40

###### g_variant_dict_insert

Inserts a value into a `GVariantDict`.

since: 2.40

###### g_variant_dict_insert_value

Inserts (or replaces) a key in a `GVariantDict`.

since: 2.40

###### g_variant_dict_lookup

Looks up a value in a `GVariantDict`.

since: 2.40

###### g_variant_dict_lookup_value

Looks up a value in a `GVariantDict`.

since: 2.40

###### g_variant_dict_ref

Increases the reference count on `dict`.

since: 2.40

###### g_variant_dict_remove

Removes a key and its associated value from a `GVariantDict`.

since: 2.40

###### g_variant_dict_unref

Decreases the reference count on `dict`.

since: 2.40