Glib.Variant.Gvariant is a variant datatype; it can contain one or more values along with information about the type of the values.
A Glib.Variant.Gvariant may contain simple types, like an integer, or a boolean value; or complex types, like an array of two strings, or a dictionary of key value pairs. A Glib.Variant.Gvariant is also immutable: once it's been created neither its type nor its content can be modified further.
GVariant is useful whenever data needs to be serialized, for example when sending method parameters in D-Bus, or when saving settings using GSettings.
When creating a new Glib.Variant.Gvariant, you pass the data you want to store in it along with a string representing the type of data you wish to pass to it.
For instance, if you want to create a Glib.Variant.Gvariant holding an integer value you can use:
GVariant *v = g_variant_new ("u", 40);
The string "u" in the first argument tells Glib.Variant.Gvariant that the data passed to the constructor (40) is going to be an unsigned integer.
More advanced examples of Glib.Variant.Gvariant in use can be found in documentation for [GVariant format strings][gvariant-format-strings-pointers].
The range of possible values is determined by the type.
The type system used by Glib.Variant.Gvariant is Glib.Variant.Gvariant_Type.
Glib.Variant.Gvariant instances always have a type and a value (which are given at construction time). The type and value of a Glib.Variant.Gvariant instance can never change other than by the Glib.Variant.Gvariant itself being destroyed. A Glib.Variant.Gvariant cannot contain a pointer.
Glib.Variant.Gvariant is reference counted using Glib.Variant.Ref and Glib.Variant.Unref. Glib.Variant.Gvariant also has floating reference counts -- see Glib.Variant.Ref_Sink.
Glib.Variant.Gvariant is completely threadsafe. A Glib.Variant.Gvariant instance can be concurrently accessed in any way from any number of threads without problems.
Glib.Variant.Gvariant is heavily optimised for dealing with data in serialized form. It works particularly well with data located in memory-mapped files. It can perform nearly all deserialization operations in a small constant time, usually touching only a single memory page. Serialized Glib.Variant.Gvariant data can also be sent over the network.
Glib.Variant.Gvariant is largely compatible with D-Bus. Almost all types of Glib.Variant.Gvariant instances can be sent over D-Bus. See Glib.Variant.Gvariant_Type for exceptions. (However, Glib.Variant.Gvariant's serialization format is not the same as the serialization format of a D-Bus message body: use Gdbus.Message.Gdbus_Message, in the gio library, for those.)
For space-efficiency, the Glib.Variant.Gvariant serialization format does not automatically include the variant's length, type or endianness, which must either be implied from context (such as knowledge that a particular file format always contains a little-endian G_VARIANT_TYPE_VARIANT which occupies the whole length of the file) or supplied out-of-band (for instance, a length, type and/or endianness indicator could be placed at the beginning of a file, network message or network stream).
A Glib.Variant.Gvariant's size is limited mainly by any lower level operating system constraints, such as the number of bits in Gsize. For example, it is reasonable to have a 2GB file mapped into memory with Gmapped.File.Gmapped_File, and call g_variant_new_from_data on it.
For convenience to C programmers, Glib.Variant.Gvariant features powerful varargs-based value construction and destruction. This feature is designed to be embedded in other libraries.
There is a Python-inspired text language for describing Glib.Variant.Gvariant values. Glib.Variant.Gvariant includes a printer for this language and a parser with type inferencing.
## Memory Use
Glib.Variant.Gvariant tries to be quite efficient with respect to memory use. This section gives a rough idea of how much memory is used by the current implementation. The information here is subject to change in the future.
The memory allocated by Glib.Variant.Gvariant can be grouped into 4 broad purposes: memory for serialized data, memory for the type information cache, buffer management memory and memory for the Glib.Variant.Gvariant structure itself.
## Serialized Data Memory
This is the memory that is used for storing GVariant data in serialized form. This is what would be sent over the network or what would end up on disk, not counting any indicator of the endianness, or of the length or type of the top-level variant.
The amount of memory required to store a boolean is 1 byte. 16, 32 and 64 bit integers and double precision floating point numbers use their "natural" size. Strings (including object path and signature strings) are stored with a nul terminator, and as such use the length of the string plus 1 byte.
Maybe types use no space at all to represent the null value and use the same amount of space (sometimes plus one byte) as the equivalent non-maybe-typed value to represent the non-null case.
Arrays use the amount of space required to store each of their members, concatenated. Additionally, if the items stored in an array are not of a fixed-size (ie: strings, other arrays, etc) then an additional framing offset is stored for each item. The size of this offset is either 1, 2 or 4 bytes depending on the overall size of the container. Additionally, extra padding bytes are added as required for alignment of child values.
Tuples (including dictionary entries) use the amount of space required to store each of their members, concatenated, plus one framing offset (as per arrays) for each non-fixed-sized item in the tuple, except for the last one. Additionally, extra padding bytes are added as required for alignment of child values.
Variants use the same amount of space as the item inside of the variant, plus 1 byte, plus the length of the type string for the item inside the variant.
As an example, consider a dictionary mapping strings to variants. In the case that the dictionary is empty, 0 bytes are required for the serialization.
If we add an item "width" that maps to the int32 value of 500 then we will use 4 byte to store the int32 (so 6 for the variant containing it) and 6 bytes for the string. The variant must be aligned to 8 after the 6 bytes of the string, so that's 2 extra bytes. 6 (string) + 2 (padding) + 6 (variant) is 14 bytes used for the dictionary entry. An additional 1 byte is added to the array as a framing offset making a total of 15 bytes.
If we add another entry, "title" that maps to a nullable string that happens to have a value of null, then we use 0 bytes for the null value (and 3 bytes for the variant to contain it along with its type string) plus 6 bytes for the string. Again, we need 2 padding bytes. That makes a total of 6 + 2 + 3 = 11 bytes.
We now require extra padding between the two items in the array. After the 14 bytes of the first item, that's 2 bytes required. We now require 2 framing offsets for an extra two bytes. 14 + 2 + 11 + 2 = 29 bytes to encode the entire two-item dictionary.
## Type Information Cache
For each GVariant type that currently exists in the program a type information structure is kept in the type information cache. The type information structure is required for rapid deserialization.
Continuing with the above example, if a Glib.Variant.Gvariant exists with the type "a{sv}" then a type information struct will exist for "a{sv}", "{sv}", "s", and "v". Multiple uses of the same type will share the same type information. Additionally, all single-digit types are stored in read-only static memory and do not contribute to the writable memory footprint of a program using Glib.Variant.Gvariant.
Aside from the type information structures stored in read-only memory, there are two forms of type information. One is used for container types where there is a single element type: arrays and maybe types. The other is used for container types where there are multiple element types: tuples and dictionary entries.
Array type info structures are 6 * sizeof (void *), plus the memory required to store the type string itself. This means that on 32-bit systems, the cache entry for "a{sv}" would require 30 bytes of memory (plus malloc overhead).
Tuple type info structures are 6 * sizeof (void *), plus 4 * sizeof (void *) for each item in the tuple, plus the memory required to store the type string itself. A 2-item tuple, for example, would have a type information structure that consumed writable memory in the size of 14 * sizeof (void *) (plus type string) This means that on 32-bit systems, the cache entry for "{sv}" would require 61 bytes of memory (plus malloc overhead).
This means that in total, for our "a{sv}" example, 91 bytes of type information would be allocated.
The type information cache, additionally, uses a GHash_Table to store and look up the cached items and stores a pointer to this hash table in static storage. The hash table is freed when there are zero items in the type cache.
Although these sizes may seem large it is important to remember that a program will probably only have a very small number of different types of values in it and that only one type information structure is required for many different values of the same type.
## Buffer Management Memory
Glib.Variant.Gvariant uses an internal buffer management structure to deal with the various different possible sources of serialized data that it uses. The buffer is responsible for ensuring that the correct call is made when the data is no longer in use by Glib.Variant.Gvariant. This may involve a g_free or a g_slice_free or even g_mapped_file_unref.
One buffer management structure is used for each chunk of serialized data. The size of the buffer management structure is 4 * (void *). On 32-bit systems, that's 16 bytes.
## GVariant structure
The size of a Glib.Variant.Gvariant structure is 6 * (void *). On 32-bit systems, that's 24 bytes.
Glib.Variant.Gvariant structures only exist if they are explicitly created with API calls. For example, if a Glib.Variant.Gvariant is constructed out of serialized data for the example given above (with the dictionary) then although there are 9 individual values that comprise the entire dictionary (two keys, two values, two variants containing the values, two dictionary entries, plus the dictionary itself), only 1 Glib.Variant.Gvariant instance exists -- the one referring to the dictionary.
If calls are made to start accessing the other values then Glib.Variant.Gvariant instances will exist for those values only for as long as they are in use (ie: until you call Glib.Variant.Unref). The type information is shared. The serialized data and the buffer management structure for that serialized data is shared by the child.
## Summary
To put the entire example together, for our dictionary mapping strings to variants (with two entries, as given above), we are using 91 bytes of memory for type information, 29 bytes of memory for the serialized data, 16 bytes for buffer management and 24 bytes for the Glib.Variant.Gvariant instance, or a total of 160 bytes, plus malloc overhead. If we were to use Glib.Variant.Get_Child_Value to access the two dictionary entries, we would use an additional 48 bytes. If we were to have other dictionaries of the same type, we would use more memory for the serialized data and buffer management for those dictionaries, but the type information would be shared.
function Byteswap (Self : Gvariant) return Gvariant
Performs a byteswapping operation on the contents of Value. The result is that all multi-byte numeric data contained in Value is byteswapped. That includes 16, 32, and 64bit signed and unsigned integers as well as file handles and double precision floating point values. This function is an identity mapping on any value that does not contain multi-byte numeric data. That include strings, booleans, bytes and containers containing only these things (recursively). While this function can safely handle untrusted, non-normal data, it is recommended to check whether the input is in normal form beforehand, using Glib.Variant.Is_Normal_Form, and to reject non-normal inputs if your application can be strict about what inputs it rejects. The returned value is always in normal form and is marked as trusted. A full, not floating, reference is returned. Since: gtk+ 2.24
the byteswapped form of Value. Has transfer-ownership='full'.
function Check_Format_String
(Self : Gvariant;
Format_String : UTF8_String;
Copy_Only : Boolean) return Boolean
Checks if calling g_variant_get with Format_String on Value would be valid from a type-compatibility standpoint. Format_String is assumed to be a valid format string (from a syntactic standpoint). If Copy_Only is True then this function additionally checks that it would be safe to call Glib.Variant.Unref on Value immediately after the call to g_variant_get without invalidating the result. This is only possible if deep copies are made (ie: there are no pointers to the data inside of the soon-to-be-freed Glib.Variant.Gvariant instance). If this check fails then a g_critical is printed and False is returned. This function is meant to be used by functions that wish to provide varargs accessors to Glib.Variant.Gvariant values of uncertain values (eg: g_variant_lookup or g_menu_model_get_item_attribute). Since: gtk+ 2.34
a valid Glib.Variant.Gvariant format string
True to ensure the format string makes deep copies
True if Format_String is safe to use
function Classify (Self : Gvariant) return GVariant_Class
Classifies Value according to its top-level type. Since: gtk+ 2.24
the Glib.Variant.GVariant_Class of Value
function Copy (Self : Gvariant_Type) return Gvariant_Type
Makes a copy of a Glib.Variant.Gvariant_Type. It is appropriate to call Glib.Variant.Free on the return value. Type may not be null.
a new Glib.Variant.Gvariant_Type Since 2.24
function Dup_Bytestring_Array
(Self : Gvariant;
Length : access Gsize := null) return GNAT.Strings.String_List
Gets the contents of an array of array of bytes Glib.Variant.Gvariant. This call makes a deep copy; the return result should be released with g_strfreev. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.26
the length of the result, or null
an array of strings
function Dup_Objv
(Self : Gvariant;
Length : access Gsize := null) return GNAT.Strings.String_List
Gets the contents of an array of object paths Glib.Variant.Gvariant. This call makes a deep copy; the return result should be released with g_strfreev. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.30
the length of the result, or null
an array of strings
function Dup_String
(Self : Gvariant;
Length : access Gsize := null) return UTF8_String
Similar to Glib.Variant.Get_String except that instead of returning a constant string, the string is duplicated. The string will always be UTF-8 encoded. The return value must be freed using g_free. Since: gtk+ 2.24
a pointer to a Gsize, to store the length
a newly allocated string, UTF-8 encoded
function Dup_String (Self : Gvariant_Type) return UTF8_String
Returns a newly-allocated copy of the type string corresponding to Type. The returned string is nul-terminated. It is appropriate to call g_free on the return value.
the corresponding type string Since 2.24
function Dup_Strv
(Self : Gvariant;
Length : access Gsize := null) return GNAT.Strings.String_List
Gets the contents of an array of strings Glib.Variant.Gvariant. This call makes a deep copy; the return result should be released with g_strfreev. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.24
the length of the result, or null
an array of strings
function Element (Self : Gvariant_Type) return Gvariant_Type
Determines the element type of an array or maybe type. This function may only be used with array or maybe types.
the element type of Type Since 2.24
function First (Self : Gvariant_Type) return Gvariant_Type
Determines the first item type of a tuple or dictionary entry type. This function may only be used with tuple or dictionary entry types, but must not be used with the generic tuple type G_VARIANT_TYPE_TUPLE. In the case of a dictionary entry type, this returns the type of the key. null is returned in case of Type being G_VARIANT_TYPE_UNIT. This call, together with Glib.Variant.Next provides an iterator interface over tuple and dictionary entry types.
the first item type of Type, or null Since 2.24
procedure Free (Self : Gvariant_Type)
Frees a Glib.Variant.Gvariant_Type that was allocated with Glib.Variant.Copy, g_variant_type_new or one of the container type constructor functions. In the case that Type is null, this function does nothing. Since 2.24
function From_Object (Object : System.Address) return Gvariant
function From_Object_Free (B : access Gvariant'Class) return Gvariant
procedure G_New (Self : out Gvariant_Type; Type_String : UTF8_String)
Creates a new Glib.Variant.Gvariant_Type corresponding to the type string given by Type_String. It is appropriate to call Glib.Variant.Free on the return value. It is a programmer error to call this function with an invalid type string. Use Glib.Variant.String_Is_Valid if you are unsure. Since: gtk+ 2.24
a valid GVariant type string
procedure G_New_Boolean (Self : out Gvariant; Value : Boolean)
Creates a new boolean Glib.Variant.Gvariant instance -- either True or False. Since: gtk+ 2.24
a Boolean value
procedure G_New_Byte (Self : out Gvariant; Value : Guint8)
Creates a new byte Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Guint8 value
procedure G_New_Bytestring (Self : out Gvariant; String : Guint8_Array)
Creates an array-of-bytes Glib.Variant.Gvariant with the contents of String. This function is just like g_variant_new_string except that the string need not be valid UTF-8. The nul terminator character at the end of the string is stored in the array. Since: gtk+ 2.26
a normal nul-terminated string in no particular encoding
procedure G_New_Bytestring_Array
(Self : out Gvariant;
Strv : GNAT.Strings.String_List;
Length : Gssize)
Constructs an array of bytestring Glib.Variant.Gvariant from the given array of strings. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.26
an array of strings
the length of Strv, or -1
procedure G_New_Dict_Entry
(Self : out Gvariant;
Key : Gvariant;
Value : Gvariant)
Creates a new dictionary entry Glib.Variant.Gvariant. Key and Value must be non-null. Key must be a value of a basic type (ie: not a container). If the Key or Value are floating references (see Glib.Variant.Ref_Sink), the new instance takes ownership of them as if via Glib.Variant.Ref_Sink. Since: gtk+ 2.24
a basic Glib.Variant.Gvariant, the key
a Glib.Variant.Gvariant, the value
procedure G_New_Dict_Entry
(Self : out Gvariant_Type;
Key : Gvariant_Type;
Value : Gvariant_Type)
Constructs the type corresponding to a dictionary entry with a key of type Key and a value of type Value. It is appropriate to call Glib.Variant.Free on the return value.
a basic Glib.Variant.Gvariant_Type
a Glib.Variant.Gvariant_Type
procedure G_New_Double (Self : out Gvariant; Value : Gdouble)
Creates a new double Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Gdouble floating point value
procedure G_New_From_Bytes
(Self : out Gvariant;
The_Type : Gvariant_Type;
Bytes : Glib.Bytes.Gbytes;
Trusted : Boolean)
Constructs a new serialized-mode Glib.Variant.Gvariant instance. This is the inner interface for creation of new serialized values that gets called from various functions in gvariant.c. A reference is taken on Bytes. The data in Bytes must be aligned appropriately for the Type being loaded. Otherwise this function will internally create a copy of the memory (since GLib 2.60) or (in older versions) fail and exit the process. Since: gtk+ 2.36
a Glib.Variant.Gvariant_Type
a Glib.Bytes.Gbytes
if the contents of Bytes are trusted
procedure G_New_Handle (Self : out Gvariant; Value : Gint32)
Creates a new handle Glib.Variant.Gvariant instance. By convention, handles are indexes into an array of file descriptors that are sent alongside a D-Bus message. If you're not interacting with D-Bus, you probably don't need them. Since: gtk+ 2.24
a Gint32 value
procedure G_New_Int16 (Self : out Gvariant; Value : Gint16)
Creates a new int16 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Gint16 value
procedure G_New_Int32 (Self : out Gvariant; Value : Gint32)
Creates a new int32 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Gint32 value
procedure G_New_Int64 (Self : out Gvariant; Value : Gint64)
Creates a new int64 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Gint64 value
procedure G_New_Object_Path
(Self : out Gvariant;
Object_Path : UTF8_String)
Creates a D-Bus object path Glib.Variant.Gvariant with the contents of Object_Path. Object_Path must be a valid D-Bus object path. Use Glib.Variant.Is_Object_Path if you're not sure. Since: gtk+ 2.24
a normal C nul-terminated string
procedure G_New_Objv
(Self : out Gvariant;
Strv : GNAT.Strings.String_List;
Length : Gssize)
Constructs an array of object paths Glib.Variant.Gvariant from the given array of strings. Each string must be a valid Glib.Variant.Gvariant object path; see Glib.Variant.Is_Object_Path. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.30
an array of strings
the length of Strv, or -1
procedure G_New_Signature (Self : out Gvariant; Signature : UTF8_String)
Creates a D-Bus type signature Glib.Variant.Gvariant with the contents of String. String must be a valid D-Bus type signature. Use Glib.Variant.Is_Signature if you're not sure. Since: gtk+ 2.24
a normal C nul-terminated string
procedure G_New_String (Self : out Gvariant; String : UTF8_String)
Creates a string Glib.Variant.Gvariant with the contents of String. String must be valid UTF-8, and must not be null. To encode potentially-null strings, use g_variant_new with ms as the [format string][gvariant-format-strings-maybe-types]. Since: gtk+ 2.24
a normal UTF-8 nul-terminated string
procedure G_New_Strv
(Self : out Gvariant;
Strv : GNAT.Strings.String_List;
Length : Gssize)
Constructs an array of strings Glib.Variant.Gvariant from the given array of strings. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.24
an array of strings
the length of Strv, or -1
procedure G_New_Take_String (Self : out Gvariant; String : UTF8_String)
Creates a string Glib.Variant.Gvariant with the contents of String. String must be valid UTF-8, and must not be null. To encode potentially-null strings, use this with g_variant_new_maybe. After this call, String belongs to the Glib.Variant.Gvariant and may no longer be modified by the caller. The memory of Data has to be dynamically allocated and will eventually be freed with g_free. You must not modify or access String in any other way after passing it to this function. It is even possible that String is immediately freed. Since: gtk+ 2.38
a normal UTF-8 nul-terminated string
procedure G_New_Uint16 (Self : out Gvariant; Value : Guint16)
Creates a new uint16 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Guint16 value
procedure G_New_Uint32 (Self : out Gvariant; Value : Guint32)
Creates a new uint32 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Guint32 value
procedure G_New_Uint64 (Self : out Gvariant; Value : Guint64)
Creates a new uint64 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Guint64 value
procedure G_New_Variant (Self : out Gvariant; Value : Gvariant)
Boxes Value. The result is a Glib.Variant.Gvariant instance representing a variant containing the original value. If Child is a floating reference (see Glib.Variant.Ref_Sink), the new instance takes ownership of Child. Since: gtk+ 2.24
a Glib.Variant.Gvariant instance
function Get_Boolean (Self : Gvariant) return Boolean
Returns the boolean value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_BOOLEAN. Since: gtk+ 2.24
True or False
function Get_Byte (Self : Gvariant) return Guint8
Returns the byte value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_BYTE. Since: gtk+ 2.24
a Guint8
function Get_Bytestring_Array
(Self : Gvariant;
Length : access Gsize := null) return GNAT.Strings.String_List
Gets the contents of an array of array of bytes Glib.Variant.Gvariant. This call makes a shallow copy; the return result should be released with g_free, but the individual strings must not be modified. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.26
the length of the result, or null
an array of constant strings
function Get_Child_Value (Self : Gvariant; Index : Gsize) return Gvariant
Reads a child item out of a container Glib.Variant.Gvariant instance. This includes variants, maybes, arrays, tuples and dictionary entries. It is an error to call this function on any other type of Glib.Variant.Gvariant. It is an error if Index_ is greater than the number of child items in the container. See Glib.Variant.N_Children. The returned value is never floating. You should free it with Glib.Variant.Unref when you're done with it. Note that values borrowed from the returned child are not guaranteed to still be valid after the child is freed even if you still hold a reference to Value, if Value has not been serialized at the time this function is called. To avoid this, you can serialize Value by calling g_variant_get_data and optionally ignoring the return value. There may be implementation specific restrictions on deeply nested values, which would result in the unit tuple being returned as the child value, instead of further nested children. Glib.Variant.Gvariant is guaranteed to handle nesting up to at least 64 levels. This function is O(1). Since: gtk+ 2.24
the index of the child to fetch
the child at the specified index. Has transfer-ownership='full'.
function Get_Data_As_Bytes (Self : Gvariant) return Glib.Bytes.Gbytes
Returns a pointer to the serialized form of a Glib.Variant.Gvariant instance. The semantics of this function are exactly the same as g_variant_get_data, except that the returned Glib.Bytes.Gbytes holds a reference to the variant data. Since: gtk+ 2.36
A new Glib.Bytes.Gbytes representing the variant data. Has transfer-ownership='full'.
function Get_Double (Self : Gvariant) return Gdouble
Returns the double precision floating point value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_DOUBLE. Since: gtk+ 2.24
a Gdouble
function Get_Handle (Self : Gvariant) return Gint32
Returns the 32-bit signed integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_HANDLE. By convention, handles are indexes into an array of file descriptors that are sent alongside a D-Bus message. If you're not interacting with D-Bus, you probably don't need them. Since: gtk+ 2.24
a Gint32
function Get_Int16 (Self : Gvariant) return Gint16
Returns the 16-bit signed integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_INT16. Since: gtk+ 2.24
a Gint16
function Get_Int32 (Self : Gvariant) return Gint32
Returns the 32-bit signed integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_INT32. Since: gtk+ 2.24
a Gint32
function Get_Int64 (Self : Gvariant) return Gint64
Returns the 64-bit signed integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_INT64. Since: gtk+ 2.24
a Gint64
function Get_Maybe (Self : Gvariant) return Gvariant
Given a maybe-typed Glib.Variant.Gvariant instance, extract its value. If the value is Nothing, then this function returns null. Since: gtk+ 2.24
the contents of Value, or null. Has transfer-ownership='full'.
function Get_Normal_Form (Self : Gvariant) return Gvariant
Gets a Glib.Variant.Gvariant instance that has the same value as Value and is trusted to be in normal form. If Value is already trusted to be in normal form then a new reference to Value is returned. If Value is not already trusted, then it is scanned to check if it is in normal form. If it is found to be in normal form then it is marked as trusted and a new reference to it is returned. If Value is found not to be in normal form then a new trusted Glib.Variant.Gvariant is created with the same value as Value. The non-normal parts of Value will be replaced with default values which are guaranteed to be in normal form. It makes sense to call this function if you've received Glib.Variant.Gvariant data from untrusted sources and you want to ensure your serialized output is definitely in normal form. If Value is already in normal form, a new reference will be returned (which will be floating if Value is floating). If it is not in normal form, the newly created Glib.Variant.Gvariant will be returned with a single non-floating reference. Typically, Glib.Variant.Take_Ref should be called on the return value from this function to guarantee ownership of a single non-floating reference to it. Since: gtk+ 2.24
a trusted Glib.Variant.Gvariant. Has transfer-ownership='full'.
function Get_Objv
(Self : Gvariant;
Length : access Gsize := null) return GNAT.Strings.String_List
Gets the contents of an array of object paths Glib.Variant.Gvariant. This call makes a shallow copy; the return result should be released with g_free, but the individual strings must not be modified. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.30
the length of the result, or null
an array of constant strings
function Get_Size (Self : Gvariant) return Gsize
Determines the number of bytes that would be required to store Value with Glib.Variant.Store. If Value has a fixed-sized type then this function always returned that fixed size. In the case that Value is already in serialized form or the size has already been calculated (ie: this function has been called before) then this function is O(1). Otherwise, the size is calculated, an operation which is approximately O(n) in the number of values involved. Since: gtk+ 2.24
the serialized size of Value
function Get_String
(Self : Gvariant;
Length : access Gsize := null) return UTF8_String
Returns the string value of a Glib.Variant.Gvariant instance with a string type. This includes the types G_VARIANT_TYPE_STRING, G_VARIANT_TYPE_OBJECT_PATH and G_VARIANT_TYPE_SIGNATURE. The string will always be UTF-8 encoded, will never be null, and will never contain nul bytes. If Length is non-null then the length of the string (in bytes) is returned there. For trusted values, this information is already known. Untrusted values will be validated and, if valid, a strlen will be performed. If invalid, a default value will be returned â for G_VARIANT_TYPE_OBJECT_PATH, this is "/", and for other types it is the empty string. It is an error to call this function with a Value of any type other than those three. The return value remains valid as long as Value exists. Since: gtk+ 2.24
a pointer to a Gsize, to store the length
the constant string, UTF-8 encoded
function Get_String_Length (Self : Gvariant_Type) return Gsize
Returns the length of the type string corresponding to the given Type. This function must be used to determine the valid extent of the memory region returned by Glib.Variant.Peek_String.
the length of the corresponding type string Since 2.24
function Get_Strv
(Self : Gvariant;
Length : access Gsize := null) return GNAT.Strings.String_List
Gets the contents of an array of strings Glib.Variant.Gvariant. This call makes a shallow copy; the return result should be released with g_free, but the individual strings must not be modified. If Length is non-null then the number of elements in the result is stored there. In any case, the resulting array will be null-terminated. For an empty array, Length will be set to 0 and a pointer to a null pointer will be returned. Since: gtk+ 2.24
the length of the result, or null
an array of constant strings
function Get_Type return Glib.GType
function Get_Type (Self : Gvariant) return Gvariant_Type
Determines the type of Value. The return value is valid for the lifetime of Value and must not be freed. Since: gtk+ 2.24
a Glib.Variant.Gvariant_Type
function Get_Type_String (Self : Gvariant) return UTF8_String
Returns the type string of Value. Unlike the result of calling Glib.Variant.Peek_String, this string is nul-terminated. This string belongs to Glib.Variant.Gvariant and must not be freed. Since: gtk+ 2.24
the type string for the type of Value
function Get_Uint16 (Self : Gvariant) return Guint16
Returns the 16-bit unsigned integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_UINT16. Since: gtk+ 2.24
a Guint16
function Get_Uint32 (Self : Gvariant) return Guint32
Returns the 32-bit unsigned integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_UINT32. Since: gtk+ 2.24
a Guint32
function Get_Uint64 (Self : Gvariant) return Guint64
Returns the 64-bit unsigned integer value of Value. It is an error to call this function with a Value of any type other than G_VARIANT_TYPE_UINT64. Since: gtk+ 2.24
a Guint64
function Get_Variant (Self : Gvariant) return Gvariant
Unboxes Value. The result is the Glib.Variant.Gvariant instance that was contained in Value. Since: gtk+ 2.24
the item contained in the variant. Has transfer-ownership='full'.
type Gvariant is new Glib.C_Boxed with null record;
type GVariant_Class is (
Class_Tuple,
Class_Array,
Class_Boolean,
Class_Double,
Class_Signature,
Class_Handle,
Class_Int32,
Class_Maybe,
…,
Class_Dict_Entry);
The range of possible top-level types of Glib.Variant.Gvariant instances.
package GVariant_Class_Properties is
new Generic_Internal_Discrete_Property (GVariant_Class);
type Gvariant_Iter is new Glib.C_Proxy;
function Gvariant_New_Boolean (Value : Boolean) return Gvariant
Creates a new boolean Glib.Variant.Gvariant instance -- either True or False. Since: gtk+ 2.24
a Boolean value
function Gvariant_New_Byte (Value : Guint8) return Gvariant
Creates a new byte Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Guint8 value
function Gvariant_New_Bytestring (String : Guint8_Array) return Gvariant
Creates an array-of-bytes Glib.Variant.Gvariant with the contents of String. This function is just like g_variant_new_string except that the string need not be valid UTF-8. The nul terminator character at the end of the string is stored in the array. Since: gtk+ 2.26
a normal nul-terminated string in no particular encoding
function Gvariant_New_Bytestring_Array
(Strv : GNAT.Strings.String_List;
Length : Gssize) return Gvariant
Constructs an array of bytestring Glib.Variant.Gvariant from the given array of strings. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.26
an array of strings
the length of Strv, or -1
function Gvariant_New_Dict_Entry
(Key : Gvariant;
Value : Gvariant) return Gvariant
Creates a new dictionary entry Glib.Variant.Gvariant. Key and Value must be non-null. Key must be a value of a basic type (ie: not a container). If the Key or Value are floating references (see Glib.Variant.Ref_Sink), the new instance takes ownership of them as if via Glib.Variant.Ref_Sink. Since: gtk+ 2.24
a basic Glib.Variant.Gvariant, the key
a Glib.Variant.Gvariant, the value
function Gvariant_New_Double (Value : Gdouble) return Gvariant
Creates a new double Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Gdouble floating point value
function Gvariant_New_From_Bytes
(The_Type : Gvariant_Type;
Bytes : Glib.Bytes.Gbytes;
Trusted : Boolean) return Gvariant
Constructs a new serialized-mode Glib.Variant.Gvariant instance. This is the inner interface for creation of new serialized values that gets called from various functions in gvariant.c. A reference is taken on Bytes. The data in Bytes must be aligned appropriately for the Type being loaded. Otherwise this function will internally create a copy of the memory (since GLib 2.60) or (in older versions) fail and exit the process. Since: gtk+ 2.36
a Glib.Variant.Gvariant_Type
a Glib.Bytes.Gbytes
if the contents of Bytes are trusted
function Gvariant_New_Handle (Value : Gint32) return Gvariant
Creates a new handle Glib.Variant.Gvariant instance. By convention, handles are indexes into an array of file descriptors that are sent alongside a D-Bus message. If you're not interacting with D-Bus, you probably don't need them. Since: gtk+ 2.24
a Gint32 value
function Gvariant_New_Int16 (Value : Gint16) return Gvariant
Creates a new int16 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Gint16 value
function Gvariant_New_Int32 (Value : Gint32) return Gvariant
Creates a new int32 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Gint32 value
function Gvariant_New_Int64 (Value : Gint64) return Gvariant
Creates a new int64 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Gint64 value
function Gvariant_New_Object_Path
(Object_Path : UTF8_String) return Gvariant
Creates a D-Bus object path Glib.Variant.Gvariant with the contents of Object_Path. Object_Path must be a valid D-Bus object path. Use Glib.Variant.Is_Object_Path if you're not sure. Since: gtk+ 2.24
a normal C nul-terminated string
function Gvariant_New_Objv
(Strv : GNAT.Strings.String_List;
Length : Gssize) return Gvariant
Constructs an array of object paths Glib.Variant.Gvariant from the given array of strings. Each string must be a valid Glib.Variant.Gvariant object path; see Glib.Variant.Is_Object_Path. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.30
an array of strings
the length of Strv, or -1
function Gvariant_New_Signature (Signature : UTF8_String) return Gvariant
Creates a D-Bus type signature Glib.Variant.Gvariant with the contents of String. String must be a valid D-Bus type signature. Use Glib.Variant.Is_Signature if you're not sure. Since: gtk+ 2.24
a normal C nul-terminated string
function Gvariant_New_String (String : UTF8_String) return Gvariant
Creates a string Glib.Variant.Gvariant with the contents of String. String must be valid UTF-8, and must not be null. To encode potentially-null strings, use g_variant_new with ms as the [format string][gvariant-format-strings-maybe-types]. Since: gtk+ 2.24
a normal UTF-8 nul-terminated string
function Gvariant_New_Strv
(Strv : GNAT.Strings.String_List;
Length : Gssize) return Gvariant
Constructs an array of strings Glib.Variant.Gvariant from the given array of strings. If Length is -1 then Strv is null-terminated. Since: gtk+ 2.24
an array of strings
the length of Strv, or -1
function Gvariant_New_Take_String (String : UTF8_String) return Gvariant
Creates a string Glib.Variant.Gvariant with the contents of String. String must be valid UTF-8, and must not be null. To encode potentially-null strings, use this with g_variant_new_maybe. After this call, String belongs to the Glib.Variant.Gvariant and may no longer be modified by the caller. The memory of Data has to be dynamically allocated and will eventually be freed with g_free. You must not modify or access String in any other way after passing it to this function. It is even possible that String is immediately freed. Since: gtk+ 2.38
a normal UTF-8 nul-terminated string
function Gvariant_New_Uint16 (Value : Guint16) return Gvariant
Creates a new uint16 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Guint16 value
function Gvariant_New_Uint32 (Value : Guint32) return Gvariant
Creates a new uint32 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Guint32 value
function Gvariant_New_Uint64 (Value : Guint64) return Gvariant
Creates a new uint64 Glib.Variant.Gvariant instance. Since: gtk+ 2.24
a Guint64 value
function Gvariant_New_Variant (Value : Gvariant) return Gvariant
Boxes Value. The result is a Glib.Variant.Gvariant instance representing a variant containing the original value. If Child is a floating reference (see Glib.Variant.Ref_Sink), the new instance takes ownership of Child. Since: gtk+ 2.24
a Glib.Variant.Gvariant instance
type Gvariant_Type is new Glib.C_Proxy;
Gvariant_Type_Boolean : constant Gvariant_Type;
Gvariant_Type_Byte : constant Gvariant_Type;
Gvariant_Type_Double : constant Gvariant_Type;
Gvariant_Type_Int16 : constant Gvariant_Type;
Gvariant_Type_Int32 : constant Gvariant_Type;
Gvariant_Type_Int64 : constant Gvariant_Type;
function Gvariant_Type_New
(Type_String : UTF8_String) return Gvariant_Type
Creates a new Glib.Variant.Gvariant_Type corresponding to the type string given by Type_String. It is appropriate to call Glib.Variant.Free on the return value. It is a programmer error to call this function with an invalid type string. Use Glib.Variant.String_Is_Valid if you are unsure. Since: gtk+ 2.24
a valid GVariant type string
function Gvariant_Type_New_Dict_Entry
(Key : Gvariant_Type;
Value : Gvariant_Type) return Gvariant_Type
Constructs the type corresponding to a dictionary entry with a key of type Key and a value of type Value. It is appropriate to call Glib.Variant.Free on the return value.
a basic Glib.Variant.Gvariant_Type
a Glib.Variant.Gvariant_Type
Gvariant_Type_String : constant Gvariant_Type;
Gvariant_Type_Uint16 : constant Gvariant_Type;
Gvariant_Type_Uint32 : constant Gvariant_Type;
Gvariant_Type_Uint64 : constant Gvariant_Type;
function Hash (Self : System.Address) return Guint
Generates a hash value for a Glib.Variant.Gvariant instance. The output of this function is guaranteed to be the same for a given value only per-process. It may change between different processor architectures or even different versions of GLib. Do not use this function as a basis for building protocols or file formats. The type of Value is System.Address only to allow use of this function with GHash_Table. Value must be a Glib.Variant.Gvariant. Since: gtk+ 2.24
a hash value corresponding to Value
function Init (Self : Gvariant_Iter; Value : Gvariant) return Gsize
Initialises (without allocating) a Glib.Variant.Gvariant_Iter. Iter may be completely uninitialised prior to this call; its old value is ignored. The iterator remains valid for as long as Value exists, and need not be freed in any way. Since: gtk+ 2.24
a container Glib.Variant.Gvariant
the number of items in Value
function Is_Array (Self : Gvariant_Type) return Boolean
Determines if the given Type is an array type. This is true if the type string for Type starts with an 'a'. This function returns True for any indefinite type for which every definite subtype is an array type -- G_VARIANT_TYPE_ARRAY, for example.
True if Type is an array type Since 2.24
function Is_Basic (Self : Gvariant_Type) return Boolean
Determines if the given Type is a basic type. Basic types are booleans, bytes, integers, doubles, strings, object paths and signatures. Only a basic type may be used as the key of a dictionary entry. This function returns False for all indefinite types except G_VARIANT_TYPE_BASIC.
True if Type is a basic type Since 2.24
function Is_Container (Self : Gvariant) return Boolean
Checks if Value is a container. Since: gtk+ 2.24
True if Value is a container
function Is_Container (Self : Gvariant_Type) return Boolean
Determines if the given Type is a container type. Container types are any array, maybe, tuple, or dictionary entry types plus the variant type. This function returns True for any indefinite type for which every definite subtype is a container -- G_VARIANT_TYPE_ARRAY, for example.
True if Type is a container type Since 2.24
function Is_Definite (Self : Gvariant_Type) return Boolean
Determines if the given Type is definite (ie: not indefinite). A type is definite if its type string does not contain any indefinite type characters ('*', '?', or 'r'). A Glib.Variant.Gvariant instance may not have an indefinite type, so calling this function on the result of Glib.Variant.Get_Type will always result in True being returned. Calling this function on an indefinite type like G_VARIANT_TYPE_ARRAY, however, will result in False being returned.
True if Type is definite Since 2.24
function Is_Dict_Entry (Self : Gvariant_Type) return Boolean
Determines if the given Type is a dictionary entry type. This is true if the type string for Type starts with a '{'. This function returns True for any indefinite type for which every definite subtype is a dictionary entry type -- G_VARIANT_TYPE_DICT_ENTRY, for example.
True if Type is a dictionary entry type Since 2.24
function Is_Floating (Self : Gvariant) return Boolean
Checks whether Value has a floating reference count. This function should only ever be used to assert that a given variant is or is not floating, or for debug purposes. To acquire a reference to a variant that might be floating, always use Glib.Variant.Ref_Sink or Glib.Variant.Take_Ref. See Glib.Variant.Ref_Sink for more information about floating reference counts. Since: gtk+ 2.26
whether Value is floating
function Is_Maybe (Self : Gvariant_Type) return Boolean
Determines if the given Type is a maybe type. This is true if the type string for Type starts with an 'm'. This function returns True for any indefinite type for which every definite subtype is a maybe type -- G_VARIANT_TYPE_MAYBE, for example.
True if Type is a maybe type Since 2.24
function Is_Normal_Form (Self : Gvariant) return Boolean
Checks if Value is in normal form. The main reason to do this is to detect if a given chunk of serialized data is in normal form: load the data into a Glib.Variant.Gvariant using g_variant_new_from_data and then use this function to check. If Value is found to be in normal form then it will be marked as being trusted. If the value was already marked as being trusted then this function will immediately return True. There may be implementation specific restrictions on deeply nested values. GVariant is guaranteed to handle nesting up to at least 64 levels. Since: gtk+ 2.24
True if Value is in normal form
function Is_Object_Path (String : UTF8_String) return Boolean
Determines if a given string is a valid D-Bus object path. You should ensure that a string is a valid D-Bus object path before passing it to g_variant_new_object_path. A valid object path starts with / followed by zero or more sequences of characters separated by / characters. Each sequence must contain only the characters [A-Z][a-z][0-9]_. No sequence (including the one following the final / character) may be empty. Since: gtk+ 2.24
a normal C nul-terminated string
True if String is a D-Bus object path
function Is_Of_Type
(Self : Gvariant;
The_Type : Gvariant_Type) return Boolean
Checks if a value has a type matching the provided type. Since: gtk+ 2.24
a Glib.Variant.Gvariant_Type
True if the type of Value matches Type
function Is_Signature (String : UTF8_String) return Boolean
Determines if a given string is a valid D-Bus type signature. You should ensure that a string is a valid D-Bus type signature before passing it to g_variant_new_signature. D-Bus type signatures consist of zero or more definite Glib.Variant.Gvariant_Type strings in sequence. Since: gtk+ 2.24
a normal C nul-terminated string
True if String is a D-Bus type signature
function Is_Subtype_Of
(Self : Gvariant_Type;
Supertype : Gvariant_Type) return Boolean
Checks if Type is a subtype of Supertype. This function returns True if Type is a subtype of Supertype. All types are considered to be subtypes of themselves. Aside from that, only indefinite types can have subtypes.
a Glib.Variant.Gvariant_Type
True if Type is a subtype of Supertype Since 2.24
function Is_Tuple (Self : Gvariant_Type) return Boolean
Determines if the given Type is a tuple type. This is true if the type string for Type starts with a '(' or if Type is G_VARIANT_TYPE_TUPLE. This function returns True for any indefinite type for which every definite subtype is a tuple type -- G_VARIANT_TYPE_TUPLE, for example.
True if Type is a tuple type Since 2.24
function Is_Variant (Self : Gvariant_Type) return Boolean
Determines if the given Type is the variant type.
True if Type is the variant type Since 2.24
function Iter_New (Self : Gvariant) return Gvariant_Iter
Creates a heap-allocated Glib.Variant.Gvariant_Iter for iterating over the items in Value. Use g_variant_iter_free to free the return value when you no longer need it. A reference is taken to Value and will be released only when g_variant_iter_free is called. Since: gtk+ 2.24
a new heap-allocated Glib.Variant.Gvariant_Iter
function Key (Self : Gvariant_Type) return Gvariant_Type
Determines the key type of a dictionary entry type. This function may only be used with a dictionary entry type. Other than the additional restriction, this call is equivalent to Glib.Variant.First.
the key type of the dictionary entry Since 2.24
function Lookup_Value
(Self : Gvariant;
Key : UTF8_String;
Expected_Type : Gvariant_Type) return Gvariant
Looks up a value in a dictionary Glib.Variant.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 Gvariant.Dict.Gvariant_Dict may be more efficient. Since: gtk+ 2.28
the key to look up in the dictionary
a Glib.Variant.Gvariant_Type, or null
the value of the dictionary key, or null. Has transfer-ownership='full'.
function N_Children (Self : Gvariant) return Gsize
Determines the number of children in a container Glib.Variant.Gvariant instance. This includes variants, maybes, arrays, tuples and dictionary entries. It is an error to call this function on any other type of Glib.Variant.Gvariant. For variants, the return value is always 1. For values with maybe types, it is always zero or one. For arrays, it is the length of the array. For tuples it is the number of tuple items (which depends only on the type). For dictionary entries, it is always 2 This function is O(1). Since: gtk+ 2.24
the number of children in the container
function N_Items (Self : Gvariant_Type) return Gsize
Determines the number of items contained in a tuple or dictionary entry type. This function may only be used with tuple or dictionary entry types, but must not be used with the generic tuple type G_VARIANT_TYPE_TUPLE. In the case of a dictionary entry type, this function will always return 2.
the number of items in Type Since 2.24
function Next (Self : Gvariant_Type) return Gvariant_Type
Determines the next item type of a tuple or dictionary entry type. Type must be the result of a previous call to Glib.Variant.First or Glib.Variant.Next. If called on the key type of a dictionary entry then this call returns the value type. If called on the value type of a dictionary entry then this call returns null. For tuples, null is returned when Type is the last item in a tuple.
the next Glib.Variant.Gvariant_Type after Type, or null Since 2.24
function Next_Value (Self : Gvariant_Iter) return Gvariant
Gets the next item in the container. If no more items remain then null is returned. Use Glib.Variant.Unref to drop your reference on the return value when you no longer need it. Here is an example for iterating with Glib.Variant.Next_Value:
// recursively iterate a container
void
iterate_container_recursive (GVariant *container)
{
GVariantIter iter;
GVariant *child;
g_variant_iter_init (&iter, container);
while ((child = g_variant_iter_next_value (&iter)))
{
g_print ("type '%s'\n", g_variant_get_type_string (child));
if (g_variant_is_container (child))
iterate_container_recursive (child);
g_variant_unref (child);
}
}
Since: gtk+ 2.24
a Glib.Variant.Gvariant, or null. Has transfer-ownership='full'.
Null_Gvariant : constant Gvariant;
function Parse
(The_Type : Gvariant_Type;
Text : UTF8_String;
Limit : UTF8_String := "";
Endptr : GNAT.Strings.String_List;
Error : out Glib.Error.GError) return Gvariant
Parses a Glib.Variant.Gvariant from a text representation. A single Glib.Variant.Gvariant is parsed from the content of Text. The format is described [here][gvariant-text]. The memory at Limit will never be accessed and the parser behaves as if the character at Limit is the nul terminator. This has the effect of bounding Text. If Endptr is non-null then Text is permitted to contain data following the value that this function parses and Endptr will be updated to point to the first character past the end of the text parsed by this function. If Endptr is null and there is extra data then an error is returned. If Type is non-null then the value will be parsed to have that type. This may result in additional parse errors (in the case that the parsed value doesn't fit the type) but may also result in fewer errors (in the case that the type would have been ambiguous, such as with empty arrays). In the event that the parsing is successful, the resulting Glib.Variant.Gvariant is returned. It is never floating, and must be freed with Glib.Variant.Unref. In case of any error, null will be returned. If Error is non-null then it will be set to reflect the error that occurred. Officially, the language understood by the parser is "any string produced by Glib.Variant.Print". There may be implementation specific restrictions on deeply nested values, which would result in a Glib.Error_Enums.G_Variant_Parse_Error_Recursion error. Glib.Variant.Gvariant is guaranteed to handle nesting up to at least 64 levels.
a Glib.Variant.Gvariant_Type, or null
a string containing a GVariant in text form
a pointer to the end of Text, or null
a location to store the end pointer, or null
the return location for a recoverable error
a non-floating reference to a Glib.Variant.Gvariant, or null. Has transfer-ownership='full'.
function Parse_Error_Print_Context
(Error : Glib.Error.GError;
Source_Str : UTF8_String) return UTF8_String
Pretty-prints a message showing the context of a Glib.Variant.Gvariant parse error within the string for which parsing was attempted. The resulting string is suitable for output to the console or other monospace media where newlines are treated in the usual way. The message will typically look something like one of the following:
unterminated string constant:
(1, 2, 3, 'abc
^^^^
or
unable to find a common type:
[1, 2, 3, 'str']
^ ^^^^^
The format of the message may change in a future version. Error must have come from a failed attempt to Glib.Variant.Parse and Source_Str must be exactly the same string that caused the error. If Source_Str was not nul-terminated when you passed it to Glib.Variant.Parse then you must add nul termination before using this function. Since: gtk+ 2.40
a Gerror.Gerror from the Glib.Error_Enums.GVariant_Parse_Error domain
the string that was given to the parser
the printed message
function Parse_Error_Quark return Glib.GQuark
function Parser_Get_Error_Quark return Glib.GQuark
Same as g_variant_error_quark. Deprecated since None, 1
function Peek_String (Self : Gvariant_Type) return UTF8_String
Returns the type string corresponding to the given Type. The result is not nul-terminated; in order to determine its length you must call Glib.Variant.Get_String_Length. To get a nul-terminated string, see Glib.Variant.Dup_String.
the corresponding type string (not nul-terminated) Since 2.24
function Print
(Self : Gvariant;
Type_Annotate : Boolean) return UTF8_String
Pretty-prints Value in the format understood by Glib.Variant.Parse. The format is described [here][gvariant-text]. If Type_Annotate is True, then type information is included in the output. Since: gtk+ 2.24
True if type information should be included in the output
a newly-allocated string holding the result.
function Print_String
(Self : Gvariant;
String : Glib.String.Gstring;
Type_Annotate : Boolean) return Glib.String.Gstring
Behaves as Glib.Variant.Print, but operates on a Glib.String.Gstring. If String is non-null then it is appended to and returned. Else, a new empty Glib.String.Gstring is allocated and it is returned. Since: gtk+ 2.24
a Glib.String.Gstring, or null
True if type information should be included in the output
a Glib.String.Gstring containing the string
type Property_GVariant_Class is new GVariant_Class_Properties.Property;
function Ref (Self : Gvariant) return Gvariant
Increases the reference count of Value. Since: gtk+ 2.24
the same Value. Has transfer-ownership='full'.
function Ref_Sink (Self : Gvariant) return Gvariant
Glib.Variant.Gvariant uses a floating reference count system. All functions with names starting with g_variant_new_ return floating references. Calling Glib.Variant.Ref_Sink on a Glib.Variant.Gvariant with a floating reference will convert the floating reference into a full reference. Calling Glib.Variant.Ref_Sink on a non-floating Glib.Variant.Gvariant results in an additional normal reference being added. In other words, if the Value is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference. If the Value is not floating, then this call adds a new normal reference increasing the reference count by one. All calls that result in a Glib.Variant.Gvariant instance being inserted into a container will call Glib.Variant.Ref_Sink on the instance. This means that if the value was just created (and has only its floating reference) then the container will assume sole ownership of the value at that point and the caller will not need to unreference it. This makes certain common styles of programming much easier while still maintaining normal refcounting semantics in situations where values are not floating. Since: gtk+ 2.24
the same Value. Has transfer-ownership='full'.
procedure Store (Self : Gvariant; Data : System.Address)
Stores the serialized form of Value at Data. Data should be large enough. See Glib.Variant.Get_Size. The stored data is in machine native byte order but may not be in fully-normalised form if read from an untrusted source. See Glib.Variant.Get_Normal_Form for a solution. As with g_variant_get_data, to be able to deserialize the serialized variant successfully, its type and (if the destination machine might be different) its endianness must also be available. This function is approximately O(n) in the size of Data. Since: gtk+ 2.24
the location to store the serialized data at
function String_Get_Depth (Type_String : UTF8_String) return Gsize
function String_Is_Valid (Type_String : UTF8_String) return Boolean
Checks if Type_String is a valid GVariant type string. This call is equivalent to calling g_variant_type_string_scan and confirming that the following character is a nul terminator.
a pointer to any string
True if Type_String is exactly one valid type string Since 2.24
function Take_Ref (Self : Gvariant) return Gvariant
If Value is floating, sink it. Otherwise, do nothing. Typically you want to use Glib.Variant.Ref_Sink in order to automatically do the correct thing with respect to floating or non-floating references, but there is one specific scenario where this function is helpful. The situation where this function is helpful is when creating an API that allows the user to provide a callback function that returns a Glib.Variant.Gvariant. We certainly want to allow the user the flexibility to return a non-floating reference from this callback (for the case where the value that is being returned already exists). At the same time, the style of the Glib.Variant.Gvariant API makes it likely that for newly-created Glib.Variant.Gvariant instances, the user can be saved some typing if they are allowed to return a Glib.Variant.Gvariant with a floating reference. Using this function on the return value of the user's callback allows the user to do whichever is more convenient for them. The caller will always receives exactly one full reference to the value: either the one that was returned in the first place, or a floating reference that has been converted to a full reference. This function has an odd interaction when combined with Glib.Variant.Ref_Sink running at the same time in another thread on the same Glib.Variant.Gvariant instance. If Glib.Variant.Ref_Sink runs first then the result will be that the floating reference is converted to a hard reference. If Glib.Variant.Take_Ref runs first then the result will be that the floating reference is converted to a hard reference and an additional reference on top of that one is added. It is best to avoid this situation.
the same Value. Has transfer-ownership='full'.
procedure Unref (Self : Gvariant)
Decreases the reference count of Value. When its reference count drops to 0, the memory used by the variant is freed. Since: gtk+ 2.24
function Value (Self : Gvariant_Type) return Gvariant_Type
Determines the value type of a dictionary entry type. This function may only be used with a dictionary entry type.
the value type of the dictionary entry Since 2.24