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<div class="refentry">
<a name="id-1.1.89"></a><div class="titlepage"></div>
<div class="refnamediv">
<h2>&lt;GVariantType&gt;</h2>
<p>&lt;GVariantType&gt;</p>
</div>
<div class="refsect1">
<a name="id-1.1.89.2"></a><h2>Description</h2>
<p>This section introduces the GVariant type system. It is based, in
large part, on the D-Bus type system, with two major changes and
some minor lifting of restrictions. The
[D-Bus specification](http://dbus.freedesktop.org/doc/dbus-specification.html),
therefore, provides a significant amount of
information that is useful when working with GVariant.
</p>
<p>The first major change with respect to the D-Bus type system is the
introduction of maybe (or "nullable") types.  Any type in GVariant can be
converted to a maybe type, in which case, "nothing" (or "null") becomes a
valid value.  Maybe types have been added by introducing the
character "m" to type strings.
</p>
<p>The second major change is that the GVariant type system supports the
concept of "indefinite types" -- types that are less specific than
the normal types found in D-Bus.  For example, it is possible to speak
of "an array of any type" in GVariant, where the D-Bus type system
would require you to speak of "an array of integers" or "an array of
strings".  Indefinite types have been added by introducing the
characters "*", "?" and "r" to type strings.
</p>
<p>Finally, all arbitrary restrictions relating to the complexity of
types are lifted along with the restriction that dictionary entries
may only appear nested inside of arrays.
</p>
<p>Just as in D-Bus, GVariant types are described with strings ("type
strings").  Subject to the differences mentioned above, these strings
are of the same form as those found in DBus.  Note, however: D-Bus
always works in terms of messages and therefore individual type
strings appear nowhere in its interface.  Instead, "signatures"
are a concatenation of the strings of the type of each argument in a
message.  GVariant deals with single values directly so GVariant type
strings always describe the type of exactly one value.  This means
that a D-Bus signature string is generally not a valid GVariant type
string -- except in the case that it is the signature of a message
containing exactly one argument.
</p>
<p>An indefinite type is similar in spirit to what may be called an
abstract type in other type systems.  No value can exist that has an
indefinite type as its type, but values can exist that have types
that are subtypes of indefinite types.  That is to say,
<code class="function">g_variant_get_type()</code> will never return an indefinite type, but
calling <code class="function">g_variant_is_of_type()</code> with an indefinite type may return
<code class="constant">TRUE</code>.  For example, you cannot have a value that represents "an
array of no particular type", but you can have an "array of integers"
which certainly matches the type of "an array of no particular type",
since "array of integers" is a subtype of "array of no particular
type".
</p>
<p>This is similar to how instances of abstract classes may not
directly exist in other type systems, but instances of their
non-abstract subtypes may.  For example, in GTK, no object that has
the type of <span class="type">GtkBin</span> can exist (since <span class="type">GtkBin</span> is an abstract class),
but a <span class="type">GtkWindow</span> can certainly be instantiated, and you would say
that the <span class="type">GtkWindow</span> is a <span class="type">GtkBin</span> (since <span class="type">GtkWindow</span> is a subclass of
<span class="type">GtkBin</span>).
</p>
<div class="refsect2">
<a name="id-1.1.89.2.9"></a><h3>GVariant Type Strings</h3>
<p>A GVariant type string can be any of the following:
</p>
<p>- any basic type string (listed below)
</p>
<p>- "v", "r" or "*"
</p>
<p>- one of the characters 'a' or 'm', followed by another type string
</p>
<p>- the character '(', followed by a concatenation of zero or more other
  type strings, followed by the character ')'
</p>
<p>- the character '{', followed by a basic type string (see below),
  followed by another type string, followed by the character '}'
</p>
<p>A basic type string describes a basic type (as per
<code class="function">g_variant_type_is_basic()</code>) and is always a single character in length.
The valid basic type strings are "b", "y", "n", "q", "i", "u", "x", "t",
"h", "d", "s", "o", "g" and "?".
</p>
<p>The above definition is recursive to arbitrary depth. "aaaaai" and
"(ui(nq((y)))s)" are both valid type strings, as is
"a(aa(ui)(qna{ya(yd)}))". In order to not hit memory limits, <span class="type">GVariant</span>
imposes a limit on recursion depth of 65 nested containers. This is the
limit in the D-Bus specification (64) plus one to allow a <span class="type">GDBusMessage</span> to
be nested in a top-level tuple.
</p>
<p>The meaning of each of the characters is as follows:
- <code class="code">b</code>: the type string of <code class="constant">G_VARIANT_TYPE_BOOLEAN</code>; a boolean value.
- <code class="code">y</code>: the type string of <code class="constant">G_VARIANT_TYPE_BYTE</code>; a byte.
- <code class="code">n</code>: the type string of <code class="constant">G_VARIANT_TYPE_INT16</code>; a signed 16 bit integer.
- <code class="code">q</code>: the type string of <code class="constant">G_VARIANT_TYPE_UINT16</code>; an unsigned 16 bit integer.
- <code class="code">i</code>: the type string of <code class="constant">G_VARIANT_TYPE_INT32</code>; a signed 32 bit integer.
- <code class="code">u</code>: the type string of <code class="constant">G_VARIANT_TYPE_UINT32</code>; an unsigned 32 bit integer.
- <code class="code">x</code>: the type string of <code class="constant">G_VARIANT_TYPE_INT64</code>; a signed 64 bit integer.
- <code class="code">t</code>: the type string of <code class="constant">G_VARIANT_TYPE_UINT64</code>; an unsigned 64 bit integer.
- <code class="code">h</code>: the type string of <code class="constant">G_VARIANT_TYPE_HANDLE</code>; a signed 32 bit value
  that, by convention, is used as an index into an array of file
  descriptors that are sent alongside a D-Bus message.
- <code class="code">d</code>: the type string of <code class="constant">G_VARIANT_TYPE_DOUBLE</code>; a double precision
  floating point value.
- <code class="code">s</code>: the type string of <code class="constant">G_VARIANT_TYPE_STRING</code>; a string.
- <code class="code">o</code>: the type string of <code class="constant">G_VARIANT_TYPE_OBJECT_PATH</code>; a string in the form
  of a D-Bus object path.
- <code class="code">g</code>: the type string of <code class="constant">G_VARIANT_TYPE_SIGNATURE</code>; a string in the form of
  a D-Bus type signature.
- <code class="code">?</code>: the type string of <code class="constant">G_VARIANT_TYPE_BASIC</code>; an indefinite type that
  is a supertype of any of the basic types.
- <code class="code">v</code>: the type string of <code class="constant">G_VARIANT_TYPE_VARIANT</code>; a container type that
  contain any other type of value.
- <code class="code">a</code>: used as a prefix on another type string to mean an array of that
  type; the type string "ai", for example, is the type of an array of
  signed 32-bit integers.
- <code class="code">m</code>: used as a prefix on another type string to mean a "maybe", or
  "nullable", version of that type; the type string "ms", for example,
  is the type of a value that maybe contains a string, or maybe contains
  nothing.
- <code class="code">()</code>: used to enclose zero or more other concatenated type strings to
  create a tuple type; the type string "(is)", for example, is the type of
  a pair of an integer and a string.
- <code class="code">r</code>: the type string of <code class="constant">G_VARIANT_TYPE_TUPLE</code>; an indefinite type that is
  a supertype of any tuple type, regardless of the number of items.
- <code class="code">{}</code>: used to enclose a basic type string concatenated with another type
  string to create a dictionary entry type, which usually appears inside of
  an array to form a dictionary; the type string "a{sd}", for example, is
  the type of a dictionary that maps strings to double precision floating
  point values.
</p>
  <p>The first type (the basic type) is the key type and the second type is
  the value type. The reason that the first type is restricted to being a
  basic type is so that it can easily be hashed.
- <code class="code">*</code>: the type string of <code class="constant">G_VARIANT_TYPE_ANY</code>; the indefinite type that is
  a supertype of all types.  Note that, as with all type strings, this
  character represents exactly one type. It cannot be used inside of tuples
  to mean "any number of items".
</p>
<p>Any type string of a container that contains an indefinite type is,
itself, an indefinite type. For example, the type string "a*"
(corresponding to <code class="constant">G_VARIANT_TYPE_ARRAY</code>) is an indefinite type
that is a supertype of every array type. "(*s)" is a supertype
of all tuples that contain exactly two items where the second
item is a string.
</p>
<p>"a{?*}" is an indefinite type that is a supertype of all arrays
containing dictionary entries where the key is any basic type and
the value is any type at all.  This is, by definition, a dictionary,
so this type string corresponds to <code class="constant">G_VARIANT_TYPE_DICTIONARY</code>. Note
that, due to the restriction that the key of a dictionary entry must
be a basic type, "{**}" is not a valid type string.</p>
</div>
</div>
<div class="refsect1">
<a name="id-1.1.89.3"></a><h2>Functions</h2>
<div class="refsect2">
<a name="id-1.1.89.3.2"></a><h3>copy</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:copy self))
</pre></div>
<p>Makes a copy of a <span class="type">GVariantType</span>.  It is appropriate to call
<code class="function">g_variant_type_free()</code> on the return value.  <em class="parameter"><code>type</code></em> may not be <code class="constant">NULL</code>.</p>
<div class="refsect3">
<a name="id-1.1.89.3.2.4"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.3"></a><h3>dup-string</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:dup-string self))
</pre></div>
<p>Returns a newly-allocated copy of the type string corresponding to
<em class="parameter"><code>type</code></em>.  The returned string is nul-terminated.  It is appropriate to
call <code class="function">g_free()</code> on the return value.</p>
<div class="refsect3">
<a name="id-1.1.89.3.3.4"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.4"></a><h3>element</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:element self))
</pre></div>
<p>Determines the element type of an array or maybe type.
</p>
<p>This function may only be used with array or maybe types.</p>
<div class="refsect3">
<a name="id-1.1.89.3.4.5"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>an array or maybe <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.5"></a><h3>equal?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:equal? self type2))
</pre></div>
<p>Compares <em class="parameter"><code>type1</code></em> and <em class="parameter"><code>type2</code></em> for equality.
</p>
<p>Only returns <code class="constant">TRUE</code> if the types are exactly equal.  Even if one type
is an indefinite type and the other is a subtype of it, <code class="constant">FALSE</code> will
be returned if they are not exactly equal.  If you want to check for
subtypes, use <code class="function">g_variant_type_is_subtype_of()</code>.
</p>
<p>The argument types of <em class="parameter"><code>type1</code></em> and <em class="parameter"><code>type2</code></em> are only <span class="type">gconstpointer</span> to
allow use with <span class="type">GHashTable</span> without function pointer casting.  For
both arguments, a valid <span class="type">GVariantType</span> must be provided.</p>
<div class="refsect3">
<a name="id-1.1.89.3.5.6"></a><h4>Parameters</h4>
<div class="informaltable"><table>
<tr>
<td class="parameter_name"><p>type1</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr>
<tr>
<td class="parameter_name"><p>type2</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">type2</code></p>
</td>
</tr>
</table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.6"></a><h3>first</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:first self))
</pre></div>
<p>Determines the first item type of a tuple or dictionary entry
type.
</p>
<p>This function may only be used with tuple or dictionary entry types,
but must not be used with the generic tuple type
<code class="constant">G_VARIANT_TYPE_TUPLE</code>.
</p>
<p>In the case of a dictionary entry type, this returns the type of
the key.
</p>
<p><code class="constant">NULL</code> is returned in case of <em class="parameter"><code>type</code></em> being <code class="constant">G_VARIANT_TYPE_UNIT</code>.
</p>
<p>This call, together with <code class="function">g_variant_type_next()</code> provides an iterator
interface over tuple and dictionary entry types.</p>
<div class="refsect3">
<a name="id-1.1.89.3.6.8"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a tuple or dictionary entry <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.7"></a><h3>free</h3>
<div class="informalexample"><pre class="programlisting">(define-values () (variant-type:free self))
</pre></div>
<p>Frees a <span class="type">GVariantType</span> that was allocated with
<code class="function">g_variant_type_copy()</code>, <code class="function">g_variant_type_new()</code> or one of the container
type constructor functions.
</p>
<p>In the case that <em class="parameter"><code>type</code></em> is <code class="constant">NULL</code>, this function does nothing.
</p>
<p>Since 2.24</p>
<div class="refsect3">
<a name="id-1.1.89.3.7.6"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span>, or <code class="constant">NULL</code></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.8"></a><h3>get-string-length</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:get-string-length self))
</pre></div>
<p>Returns the length of the type string corresponding to the given
<em class="parameter"><code>type</code></em>.  This function must be used to determine the valid extent of
the memory region returned by <code class="function">g_variant_type_peek_string()</code>.</p>
<div class="refsect3">
<a name="id-1.1.89.3.8.4"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.9"></a><h3>hash</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:hash self))
</pre></div>
<p>Hashes <em class="parameter"><code>type</code></em>.
</p>
<p>The argument type of <em class="parameter"><code>type</code></em> is only <span class="type">gconstpointer</span> to allow use with
<span class="type">GHashTable</span> without function pointer casting.  A valid
<span class="type">GVariantType</span> must be provided.</p>
<div class="refsect3">
<a name="id-1.1.89.3.9.5"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.10"></a><h3>is-array?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:is-array? self))
</pre></div>
<p>Determines if the given <em class="parameter"><code>type</code></em> is an array type.  This is true if the
type string for <em class="parameter"><code>type</code></em> starts with an 'a'.
</p>
<p>This function returns <code class="constant">TRUE</code> for any indefinite type for which every
definite subtype is an array type -- <code class="constant">G_VARIANT_TYPE_ARRAY</code>, for
example.</p>
<div class="refsect3">
<a name="id-1.1.89.3.10.5"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.11"></a><h3>is-basic?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:is-basic? self))
</pre></div>
<p>Determines if the given <em class="parameter"><code>type</code></em> is a basic type.
</p>
<p>Basic types are booleans, bytes, integers, doubles, strings, object
paths and signatures.
</p>
<p>Only a basic type may be used as the key of a dictionary entry.
</p>
<p>This function returns <code class="constant">FALSE</code> for all indefinite types except
<code class="constant">G_VARIANT_TYPE_BASIC</code>.</p>
<div class="refsect3">
<a name="id-1.1.89.3.11.7"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.12"></a><h3>is-container?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:is-container? self))
</pre></div>
<p>Determines if the given <em class="parameter"><code>type</code></em> is a container type.
</p>
<p>Container types are any array, maybe, tuple, or dictionary
entry types plus the variant type.
</p>
<p>This function returns <code class="constant">TRUE</code> for any indefinite type for which every
definite subtype is a container -- <code class="constant">G_VARIANT_TYPE_ARRAY</code>, for
example.</p>
<div class="refsect3">
<a name="id-1.1.89.3.12.6"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.13"></a><h3>is-definite?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:is-definite? self))
</pre></div>
<p>Determines if the given <em class="parameter"><code>type</code></em> is definite (ie: not indefinite).
</p>
<p>A type is definite if its type string does not contain any indefinite
type characters ('*', '?', or 'r').
</p>
<p>A <span class="type">GVariant</span> instance may not have an indefinite type, so calling
this function on the result of <code class="function">g_variant_get_type()</code> will always
result in <code class="constant">TRUE</code> being returned.  Calling this function on an
indefinite type like <code class="constant">G_VARIANT_TYPE_ARRAY</code>, however, will result in
<code class="constant">FALSE</code> being returned.</p>
<div class="refsect3">
<a name="id-1.1.89.3.13.6"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.14"></a><h3>is-dict-entry?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:is-dict-entry? self))
</pre></div>
<p>Determines if the given <em class="parameter"><code>type</code></em> is a dictionary entry type.  This is
true if the type string for <em class="parameter"><code>type</code></em> starts with a '{'.
</p>
<p>This function returns <code class="constant">TRUE</code> for any indefinite type for which every
definite subtype is a dictionary entry type --
<code class="constant">G_VARIANT_TYPE_DICT_ENTRY</code>, for example.</p>
<div class="refsect3">
<a name="id-1.1.89.3.14.5"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.15"></a><h3>is-maybe?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:is-maybe? self))
</pre></div>
<p>Determines if the given <em class="parameter"><code>type</code></em> is a maybe type.  This is true if the
type string for <em class="parameter"><code>type</code></em> starts with an 'm'.
</p>
<p>This function returns <code class="constant">TRUE</code> for any indefinite type for which every
definite subtype is a maybe type -- <code class="constant">G_VARIANT_TYPE_MAYBE</code>, for
example.</p>
<div class="refsect3">
<a name="id-1.1.89.3.15.5"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.16"></a><h3>is-subtype-of?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:is-subtype-of? self supertype))
</pre></div>
<p>Checks if <em class="parameter"><code>type</code></em> is a subtype of <em class="parameter"><code>supertype</code></em>.
</p>
<p>This function returns <code class="constant">TRUE</code> if <em class="parameter"><code>type</code></em> is a subtype of <em class="parameter"><code>supertype</code></em>.  All
types are considered to be subtypes of themselves.  Aside from that,
only indefinite types can have subtypes.</p>
<div class="refsect3">
<a name="id-1.1.89.3.16.5"></a><h4>Parameters</h4>
<div class="informaltable"><table>
<tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr>
<tr>
<td class="parameter_name"><p>supertype</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">supertype</code></p>
</td>
</tr>
</table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.17"></a><h3>is-tuple?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:is-tuple? self))
</pre></div>
<p>Determines if the given <em class="parameter"><code>type</code></em> is a tuple type.  This is true if the
type string for <em class="parameter"><code>type</code></em> starts with a '(' or if <em class="parameter"><code>type</code></em> is
<code class="constant">G_VARIANT_TYPE_TUPLE</code>.
</p>
<p>This function returns <code class="constant">TRUE</code> for any indefinite type for which every
definite subtype is a tuple type -- <code class="constant">G_VARIANT_TYPE_TUPLE</code>, for
example.</p>
<div class="refsect3">
<a name="id-1.1.89.3.17.5"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.18"></a><h3>is-variant?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:is-variant? self))
</pre></div>
<p>Determines if the given <em class="parameter"><code>type</code></em> is the variant type.</p>
<div class="refsect3">
<a name="id-1.1.89.3.18.4"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.19"></a><h3>key</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:key self))
</pre></div>
<p>Determines the key type of a dictionary entry type.
</p>
<p>This function may only be used with a dictionary entry type.  Other
than the additional restriction, this call is equivalent to
<code class="function">g_variant_type_first()</code>.</p>
<div class="refsect3">
<a name="id-1.1.89.3.19.5"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a dictionary entry <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.20"></a><h3>n-items</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:n-items self))
</pre></div>
<p>Determines the number of items contained in a tuple or
dictionary entry type.
</p>
<p>This function may only be used with tuple or dictionary entry types,
but must not be used with the generic tuple type
<code class="constant">G_VARIANT_TYPE_TUPLE</code>.
</p>
<p>In the case of a dictionary entry type, this function will always
return 2.</p>
<div class="refsect3">
<a name="id-1.1.89.3.20.6"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a tuple or dictionary entry <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.21"></a><h3>next</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:next self))
</pre></div>
<p>Determines the next item type of a tuple or dictionary entry
type.
</p>
<p><em class="parameter"><code>type</code></em> must be the result of a previous call to
<code class="function">g_variant_type_first()</code> or <code class="function">g_variant_type_next()</code>.
</p>
<p>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 <code class="constant">NULL</code>.
</p>
<p>For tuples, <code class="constant">NULL</code> is returned when <em class="parameter"><code>type</code></em> is the last item in a tuple.</p>
<div class="refsect3">
<a name="id-1.1.89.3.21.7"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a <span class="type">GVariantType</span> from a previous call</p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.22"></a><h3>value</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:value self))
</pre></div>
<p>Determines the value type of a dictionary entry type.
</p>
<p>This function may only be used with a dictionary entry type.</p>
<div class="refsect3">
<a name="id-1.1.89.3.22.5"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type</p></td>
<td class="parameter_description">
<p>a dictionary entry <span class="type">GVariantType</span></p>
<p>Passed as <code class="code">self</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.23"></a><h3>variant-type:new-tuple</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:new-tuple items))
</pre></div>
<p>Undocumented</p>
<div class="refsect3">
<a name="id-1.1.89.3.23.4"></a><h4>Parameters</h4>
<div class="informaltable"><table>
<tr>
<td class="parameter_name"><p>items</p></td>
<td class="parameter_description">
<p></p>
<p>Passed as <code class="code">items</code></p>
</td>
</tr>
<tr>
<td class="parameter_name"><p>length</p></td>
<td class="parameter_description">
<p></p>
<p>Inferred from <code class="code">items</code></p>
</td>
</tr>
</table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.24"></a><h3>variant-type:new-maybe</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:new-maybe element))
</pre></div>
<p>Undocumented</p>
<div class="refsect3">
<a name="id-1.1.89.3.24.4"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>element</p></td>
<td class="parameter_description">
<p></p>
<p>Passed as <code class="code">element</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.25"></a><h3>variant-type:new-dict-entry</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:new-dict-entry key value))
</pre></div>
<p>Undocumented</p>
<div class="refsect3">
<a name="id-1.1.89.3.25.4"></a><h4>Parameters</h4>
<div class="informaltable"><table>
<tr>
<td class="parameter_name"><p>key</p></td>
<td class="parameter_description">
<p></p>
<p>Passed as <code class="code">key</code></p>
</td>
</tr>
<tr>
<td class="parameter_name"><p>value</p></td>
<td class="parameter_description">
<p></p>
<p>Passed as <code class="code">value</code></p>
</td>
</tr>
</table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.26"></a><h3>variant-type:new-array</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:new-array element))
</pre></div>
<p>Undocumented</p>
<div class="refsect3">
<a name="id-1.1.89.3.26.4"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>element</p></td>
<td class="parameter_description">
<p></p>
<p>Passed as <code class="code">element</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.27"></a><h3>variant-type:new</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:new type-string))
</pre></div>
<p>Undocumented</p>
<div class="refsect3">
<a name="id-1.1.89.3.27.4"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type_string</p></td>
<td class="parameter_description">
<p></p>
<p>Passed as <code class="code">type-string</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.28"></a><h3>variant-type:checked-</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:checked- arg0))
</pre></div>
<p>Undocumented</p>
<div class="refsect3">
<a name="id-1.1.89.3.28.4"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>arg0</p></td>
<td class="parameter_description">
<p></p>
<p>Passed as <code class="code">arg0</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.29"></a><h3>variant-type:string-get-depth-</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:string-get-depth- type-string))
</pre></div>
<p>Undocumented</p>
<div class="refsect3">
<a name="id-1.1.89.3.29.4"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type_string</p></td>
<td class="parameter_description">
<p></p>
<p>Passed as <code class="code">type-string</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.30"></a><h3>variant-type:string-is-valid?</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return) (variant-type:string-is-valid? type-string))
</pre></div>
<p>Checks if <em class="parameter"><code>type_string</code></em> is a valid GVariant type string.  This call is
equivalent to calling <code class="function">g_variant_type_string_scan()</code> and confirming
that the following character is a nul terminator.</p>
<div class="refsect3">
<a name="id-1.1.89.3.30.4"></a><h4>Parameters</h4>
<div class="informaltable"><table><tr>
<td class="parameter_name"><p>type_string</p></td>
<td class="parameter_description">
<p>a pointer to any string</p>
<p>Passed as <code class="code">type-string</code></p>
</td>
</tr></table></div>
</div>
</div>
<div class="refsect2">
<a name="id-1.1.89.3.31"></a><h3>variant-type:string-scan</h3>
<div class="informalexample"><pre class="programlisting">(define-values (%return endptr) (variant-type:string-scan string limit))
</pre></div>
<p>Scan for a single complete and valid GVariant type string in <em class="parameter"><code>string</code></em>.
The memory pointed to by <em class="parameter"><code>limit</code></em> (or bytes beyond it) is never
accessed.
</p>
<p>If a valid type string is found, <em class="parameter"><code>endptr</code></em> is updated to point to the
first character past the end of the string that was found and <code class="constant">TRUE</code>
is returned.
</p>
<p>If there is no valid type string starting at <em class="parameter"><code>string</code></em>, or if the type
string does not end before <em class="parameter"><code>limit</code></em> then <code class="constant">FALSE</code> is returned.
</p>
<p>For the simple case of checking if a string is a valid type string,
see <code class="function">g_variant_type_string_is_valid()</code>.</p>
<div class="refsect3">
<a name="id-1.1.89.3.31.7"></a><h4>Parameters</h4>
<div class="informaltable"><table>
<tr>
<td class="parameter_name"><p>string</p></td>
<td class="parameter_description">
<p>a pointer to any string</p>
<p>Passed as <code class="code">string</code></p>
</td>
</tr>
<tr>
<td class="parameter_name"><p>limit</p></td>
<td class="parameter_description">
<p>the end of <em class="parameter"><code>string</code></em>, or <code class="constant">NULL</code></p>
<p>Passed as <code class="code">limit</code></p>
</td>
</tr>
<tr>
<td class="parameter_name"><p>endptr</p></td>
<td class="parameter_description">
<p>location to store the end pointer, or <code class="constant">NULL</code></p>
<p>Passed as <code class="code">endptr</code></p>
</td>
</tr>
</table></div>
</div>
</div>
</div>
</div>
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