glibmm 2.80.0
Public Types | Public Member Functions | Static Public Member Functions | List of all members
Glib::Variant< VariantBase > Class Reference

Specialization of Variant containing a VariantBase. More...

#include <glibmm/variant.h>

Inheritance diagram for Glib::Variant< VariantBase >:
Inheritance graph
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Public Types

using CType = GVariant *
 
using CppType = VariantBase
 
using CppContainerType = Variant< VariantBase >
 
- Public Types inherited from Glib::VariantContainerBase
using CType = GVariant *
 
using CppType = VariantContainerBase
 

Public Member Functions

 Variant ()
 Default constructor.
 
 Variant (GVariant *castitem, bool take_a_reference=false)
 GVariant constructor.
 
void get (VariantBase & variant) const
 
VariantBase get () const
 Unboxes value.
 
- Public Member Functions inherited from Glib::VariantContainerBase
 VariantContainerBase ()
 Default constructor.
 
 VariantContainerBase (GVariant *castitem, bool take_a_reference=false)
 GVariant constructor.
 
gsize get_n_children () const
 Determines the number of children in a container Variant instance.
 
void get_child (VariantBase &child, gsize index=0) const
 Reads a child item out of this instance.
 
VariantBase get_child (gsize index=0)
 Reads a child item out of a container Variant instance.
 
VariantBase get_child (gsize index=0) const
 Reads a child item out of a container Variant instance.
 
bool get_maybe (VariantBase &maybe) const
 If this is a maybe-typed instance, try to extract its value.
 
- Public Member Functions inherited from Glib::VariantBase
 VariantBase ()
 Constructs an invalid object.
 
 VariantBase (GVariant *castitem, bool make_a_copy=false)
 
 VariantBase (const VariantBase &src)
 
VariantBaseoperator= (const VariantBase &src)
 
 VariantBase (VariantBase &&other) noexcept
 
VariantBaseoperator= (VariantBase &&other) noexcept
 
 ~VariantBase () noexcept
 
void swap (VariantBase &other) noexcept
 
GVariantgobj ()
 
const GVariantgobj () const
 
GVariantgobj_copy () const
 Provides access to the underlying C instance. The caller is responsible for freeing it. Use when directly setting fields in structs.
 
 operator bool () const
 Test whether the Variant has an underlying instance.
 
void init (const GVariant *cobject, bool take_a_reference=false)
 Replace the underlying GVariant.
 
VariantType get_type () const
 Determines the type of value.
 
std::string get_type_string () const
 Returns the type string of value.
 
bool is_floating () const
 Checks whether value has a floating reference count.
 
bool is_of_type (const VariantType & type) const
 Checks if a value has a type matching the provided type.
 
bool is_container () const
 Checks if value is a container.
 
GVariantClass classify () const
 Classifies value according to its top-level type.
 
gsize get_size () const
 Determines the number of bytes that would be required to store value with g_variant_store().
 
gconstpointer get_data () const
 Returns a pointer to the serialized form of a Variant instance.
 
Glib::RefPtr< const Glib::Bytesget_data_as_bytes () const
 Returns a pointer to the serialized form of a Variant instance.
 
void store (gpointer data) const
 Stores the serialized form of value at data.
 
Glib::ustring print (bool type_annotate=false) const
 Pretty-prints value in the format understood by g_variant_parse().
 
guint hash () const
 Generates a hash value for a Variant instance.
 
bool equal (const VariantBase &other) const
 Checks if *this and other have the same type and value.
 
bool operator== (const VariantBase &other) const
 Checks if *this and other have the same type and value.
 
bool operator!= (const VariantBase &other) const
 Checks if *this and other have the same type and value.
 
bool operator< (const VariantBase &other) const =delete
 Ordering relational operators.
 
bool operator<= (const VariantBase &other) const =delete
 See operator<().
 
bool operator> (const VariantBase &other) const =delete
 See operator<().
 
bool operator>= (const VariantBase &other) const =delete
 See operator<().
 
void get_normal_form (VariantBase &result) const
 Gets a VariantBase instance that has the same value as this variant and is trusted to be in normal form.
 
bool is_normal_form () const
 Checks if value is in normal form.
 
void byteswap (VariantBase &result) const
 Performs a byteswapping operation on the contents of this variant.
 
bool check_format_string (const std::string & format_string, bool copy_only=false) const
 Checks if calling g_variant_get() with format_string on value would be valid from a type-compatibility standpoint.
 
template<typename ValueType >
ValueType get_dynamic () const
 Cast to a specific variant type and get the value.
 

Static Public Member Functions

static const VariantTypevariant_type ()
 Gets the VariantType.
 
static Variant< VariantBasecreate (const VariantBase &data)
 Creates a new Variant<VariantBase>.
 
- Static Public Member Functions inherited from Glib::VariantContainerBase
static VariantContainerBase create_tuple (const std::vector< VariantBase > &children)
 Create a tuple variant from a vector of its variant children.
 
static VariantContainerBase create_tuple (const VariantBase &child)
 Create a tuple variant with a single variant child.
 
static VariantContainerBase create_maybe (const VariantType &child_type, const VariantBase &child={})
 Depending on if child is nullptr, either wraps child inside of a maybe container or creates a Nothing instance for the given type.
 
- Static Public Member Functions inherited from Glib::VariantBase
template<class V_CastTo >
static V_CastTo cast_dynamic (const VariantBase &v)
 Cast to a specific variant type.
 
template<>
VariantContainerBase cast_dynamic (const VariantBase &v)
 

Additional Inherited Members

- Protected Attributes inherited from Glib::VariantBase
GVariantgobject_
 

Detailed Description

Specialization of Variant containing a VariantBase.

Perhaps the main use of this is as a maybe-typed (i.e. nullable) Variant, as it inherits the methods create_maybe() and get_maybe() from VariantContainerBase, plus get_n_children() to allow checking whether there is a contained value, i.e. the inner Variant is not nothing.

Since glibmm 2.28:

Member Typedef Documentation

◆ CppContainerType

◆ CppType

◆ CType

Constructor & Destructor Documentation

◆ Variant() [1/2]

Glib::Variant< VariantBase >::Variant ( )

Default constructor.

◆ Variant() [2/2]

Glib::Variant< VariantBase >::Variant ( GVariant< VariantBase > *  castitem,
bool  take_a_reference = false 
)
explicit

GVariant constructor.

Parameters
castitemThe GVariant to wrap.
take_a_referenceWhether to take an extra reference of the GVariant or not (not taking one could destroy the GVariant with the wrapper).

Member Function Documentation

◆ create()

Creates a new Variant<VariantBase>.

Parameters
dataThe value of the new Variant.
Returns
The new Variant.
Since glibmm 2.28:

◆ get() [1/2]

Unboxes value.

The result is the Variant instance that was contained in value.

Since glibmm 2.24:
Returns
The item contained in the variant.

◆ get() [2/2]

void Glib::Variant< VariantBase >::get ( VariantBase variant) const

◆ variant_type()

static const VariantType & Glib::Variant< VariantBase >::variant_type ( )
static