GLib.Variant.lookup_value

### Method

# GLib Variantlookup_value

since: 2.28

#### Declaration [src]

    GVariant*
    g_variant_lookup_value (
      GVariant* dictionary,
      const gchar* key,
      const GVariantType* expected_type
    )

#### Description [src]

Looks up a value in a dictionary `GVariant`.

This function works with dictionaries of the type a{s} (and equally well with type a{o}, but we only further discuss the string case for sake of clarity).

In the event that `dictionary` has the type a{sv}, the `expected_type` string specifies what type of value is expected to be inside of the variant. If the value inside the variant has a different type then `NULL` is returned. In the event that `dictionary` has a value type other than v then `expected_type` must directly match the value type and it is used to unpack the value directly or an error occurs.

In either case, if `key` is not found in `dictionary`, `NULL` is returned.

If the key is found and the value has the correct type, it is returned. If `expected_type` was specified then any non-`NULL` return value will have this type.

This function is currently implemented with a linear scan. If you plan to do many lookups then `GVariantDict` may be more efficient.

Available since: 2.28

#### Parameters

`key`

  Type: `const gchar*`

  The key to look up in the dictionary.

  The data is owned by the caller of the method.
  The value is a NUL terminated UTF-8 string.

`expected_type`

  Type: `GVariantType`

  A `GVariantType`, or `NULL`.

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

#### Return value

Type: `GVariant`

The value of the dictionary key, or `NULL`.

The caller of the method takes ownership of the returned data, and is responsible for freeing it.