Qt 6.x
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QJsonValue Class Reference

\inmodule QtCore\reentrant More...

#include <qjsonvalue.h>

+ Collaboration diagram for QJsonValue:

Public Types

enum  Type {
  Null = 0x0 , Bool = 0x1 , Double = 0x2 , String = 0x3 ,
  Array = 0x4 , Object = 0x5 , Undefined = 0x80
}
 This enum describes the type of the JSON value. More...
 

Public Member Functions

 QJsonValue (Type=Null)
 Creates a QJsonValue of type type.
 
 QJsonValue (bool b)
 Creates a value of type Bool, with value b.
 
 QJsonValue (double n)
 Creates a value of type Double, with value v.
 
 QJsonValue (int n)
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Creates a value of type Double, with value v.
 
 QJsonValue (qint64 v)
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Creates a value of type Double, with value v.
 
 QJsonValue (const QString &s)
 Creates a value of type String, with value s.
 
 QJsonValue (QLatin1StringView s)
 Creates a value of type String, with the Latin-1 string viewed by s.
 
QT_ASCII_CAST_WARN QJsonValue (const char *s)
 Creates a value of type String with value s, assuming UTF-8 encoding of the input.
 
 QJsonValue (const QJsonArray &a)
 Creates a value of type Array, with value a.
 
 QJsonValue (QJsonArray &&a) noexcept
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
 QJsonValue (const QJsonObject &o)
 Creates a value of type Object, with value o.
 
 QJsonValue (QJsonObject &&o) noexcept
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
 ~QJsonValue ()
 Destroys the value.
 
 QJsonValue (const QJsonValue &other) noexcept
 Creates a copy of other.
 
QJsonValueoperator= (const QJsonValue &other) noexcept
 Assigns the value stored in other to this object.
 
 QJsonValue (QJsonValue &&other) noexcept
 
QJsonValueoperator= (QJsonValue &&other) noexcept
 
void swap (QJsonValue &other) noexcept
 
QVariant toVariant () const
 Converts the value to a \l {QVariant::}{QVariant()}.
 
Type type () const
 Returns the type of the value.
 
bool isNull () const
 Returns true if the value is null.
 
bool isBool () const
 Returns true if the value contains a boolean.
 
bool isDouble () const
 Returns true if the value contains a double.
 
bool isString () const
 Returns true if the value contains a string.
 
bool isArray () const
 Returns true if the value contains an array.
 
bool isObject () const
 Returns true if the value contains an object.
 
bool isUndefined () const
 Returns true if the value is undefined.
 
bool toBool (bool defaultValue=false) const
 Converts the value to a bool and returns it.
 
int toInt (int defaultValue=0) const
 
qint64 toInteger (qint64 defaultValue=0) const
 
double toDouble (double defaultValue=0) const
 Converts the value to a double and returns it.
 
QString toString () const
 Converts the value to a QString and returns it.
 
QString toString (const QString &defaultValue) const
 Converts the value to a QString and returns it.
 
QJsonArray toArray () const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Converts the value to an array and returns it.
 
QJsonArray toArray (const QJsonArray &defaultValue) const
 Converts the value to an array and returns it.
 
QJsonObject toObject () const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Converts the value to an object and returns it.
 
QJsonObject toObject (const QJsonObject &defaultValue) const
 Converts the value to an object and returns it.
 
const QJsonValue operator[] (const QString &key) const
 Returns a QJsonValue representing the value for the key key.
 
const QJsonValue operator[] (QStringView key) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
const QJsonValue operator[] (QLatin1StringView key) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
const QJsonValue operator[] (qsizetype i) const
 Returns a QJsonValue representing the value for index i.
 
bool operator== (const QJsonValue &other) const
 Returns true if the value is equal to other.
 
bool operator!= (const QJsonValue &other) const
 Returns true if the value is not equal to other.
 

Static Public Member Functions

static QJsonValue fromVariant (const QVariant &variant)
 Converts variant to a QJsonValue and returns it.
 

Friends

class QJsonPrivate::Value
 
class QJsonArray
 
class QJsonObject
 
class QCborValue
 
Q_CORE_EXPORT QDebug operator<< (QDebug, const QJsonValue &)
 
Q_CORE_EXPORT QDataStreamoperator<< (QDataStream &, const QJsonValue &)
 

Detailed Description

\inmodule QtCore

\reentrant

Since
5.0

The QJsonValue class encapsulates a value in JSON.

A value in JSON can be one of 6 basic types:

JSON is a format to store structured data. It has 6 basic data types:

\list

A value can represent any of the above data types. In addition, QJsonValue has one special flag to represent undefined values. This can be queried with isUndefined().

The type of the value can be queried with type() or accessors like isBool(), isString(), and so on. Likewise, the value can be converted to the type stored in it using the toBool(), toString() and so on.

Values are strictly typed internally and contrary to QVariant will not attempt to do any implicit type conversions. This implies that converting to a type that is not stored in the value will return a default constructed return value.

Definition at line 23 of file qjsonvalue.h.

Member Enumeration Documentation

◆ Type

This enum describes the type of the JSON value.

\value Null A Null value \value Bool A boolean value. Use toBool() to convert to a bool. \value Double A number value. Use toDouble() to convert to a double, or toInteger() to convert to a qint64. \value String A string. Use toString() to convert to a QString. \value Array An array. Use toArray() to convert to a QJsonArray. \value Object An object. Use toObject() to convert to a QJsonObject. \value Undefined The value is undefined. This is usually returned as an error condition, when trying to read an out of bounds value in an array or a non existent key in an object.

Enumerator
Null 
Bool 
Double 
String 
Array 
Object 
Undefined 

Definition at line 26 of file qjsonvalue.h.

Constructor & Destructor Documentation

◆ QJsonValue() [1/14]

QJsonValue::QJsonValue ( Type  type = Null)

Creates a QJsonValue of type type.

The default is to create a Null value.

Definition at line 107 of file qjsonvalue.cpp.

References QCborValue::Array, Array, Bool, QCborValue::Double, Double, QCborValue::False, QCborValue::Map, QCborValue::Null, Null, Object, QCborValue::String, String, and Undefined.

◆ QJsonValue() [2/14]

QJsonValue::QJsonValue ( bool  b)

Creates a value of type Bool, with value b.

Definition at line 136 of file qjsonvalue.cpp.

◆ QJsonValue() [3/14]

QJsonValue::QJsonValue ( double  n)

Creates a value of type Double, with value v.

Definition at line 155 of file qjsonvalue.cpp.

◆ QJsonValue() [4/14]

QJsonValue::QJsonValue ( int  n)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Creates a value of type Double, with value v.

Definition at line 164 of file qjsonvalue.cpp.

◆ QJsonValue() [5/14]

QJsonValue::QJsonValue ( qint64  v)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Creates a value of type Double, with value v.

NOTE: the integer limits for IEEE 754 double precision data is 2^53 (-9007199254740992 to +9007199254740992). If you pass in values outside this range expect a loss of precision to occur.

Definition at line 175 of file qjsonvalue.cpp.

◆ QJsonValue() [6/14]

QJsonValue::QJsonValue ( const QString s)

Creates a value of type String, with value s.

Definition at line 183 of file qjsonvalue.cpp.

◆ QJsonValue() [7/14]

QJsonValue::QJsonValue ( QLatin1StringView  s)

Creates a value of type String, with the Latin-1 string viewed by s.

Definition at line 203 of file qjsonvalue.cpp.

◆ QJsonValue() [8/14]

QJsonValue::QJsonValue ( const char *  s)
inline

Creates a value of type String with value s, assuming UTF-8 encoding of the input.

You can disable this constructor by defining QT_NO_CAST_FROM_ASCII when you compile your applications.

Since
5.3

Definition at line 44 of file qjsonvalue.h.

◆ QJsonValue() [9/14]

QJsonValue::QJsonValue ( const QJsonArray a)

Creates a value of type Array, with value a.

Definition at line 211 of file qjsonvalue.cpp.

◆ QJsonValue() [10/14]

QJsonValue::QJsonValue ( QJsonArray &&  a)
noexcept

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since
6.3

Definition at line 220 of file qjsonvalue.cpp.

◆ QJsonValue() [11/14]

QJsonValue::QJsonValue ( const QJsonObject o)

Creates a value of type Object, with value o.

Definition at line 228 of file qjsonvalue.cpp.

◆ QJsonValue() [12/14]

QJsonValue::QJsonValue ( QJsonObject &&  o)
noexcept

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since
6.3

Definition at line 237 of file qjsonvalue.cpp.

◆ ~QJsonValue()

QJsonValue::~QJsonValue ( )
default

Destroys the value.

◆ QJsonValue() [13/14]

QJsonValue::QJsonValue ( const QJsonValue other)
defaultnoexcept

Creates a copy of other.

◆ QJsonValue() [14/14]

QJsonValue::QJsonValue ( QJsonValue &&  other)
noexcept
Since
5.10

Move-constructs a QJsonValue from other.

Definition at line 263 of file qjsonvalue.cpp.

References other().

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Member Function Documentation

◆ fromVariant()

QJsonValue QJsonValue::fromVariant ( const QVariant variant)
static

Converts variant to a QJsonValue and returns it.

The conversion will convert QVariant types as follows:

\table \header

\row

Definition at line 470 of file qjsonvalue.cpp.

References QJsonDocument::array(), QJsonArray::fromStringList(), QJsonObject::fromVariantHash(), QJsonArray::fromVariantList(), QJsonObject::fromVariantMap(), QUrl::FullyEncoded, QMetaType::id(), QJsonDocument::isArray(), QVariant::metaType(), Null, QJsonDocument::object(), Q_FALLTHROUGH, qt_is_finite(), QVariant::toBool(), QVariant::toDouble(), QVariant::toHash(), QVariant::toJsonArray(), QVariant::toJsonDocument(), QVariant::toJsonObject(), QVariant::toJsonValue(), QVariant::toList(), QVariant::toLongLong(), QVariant::toMap(), QVariant::toString(), QUrl::toString(), QUuid::toString(), QVariant::toStringList(), QVariant::toULongLong(), QVariant::toUrl(), QVariant::toUuid(), variant, and QUuid::WithoutBraces.

Referenced by QJsonObject::fromVariantHash().

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◆ isArray()

bool QJsonValue::isArray ( ) const
inline

Returns true if the value contains an array.

See also
toArray()

Definition at line 75 of file qjsonvalue.h.

Referenced by matches(), operator[](), QMapboxCommon::parseGeoLocation(), QGeoRouteParserOsrmV5Private::parseReply(), readGpuFeatures(), readInputFile(), and toArray().

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◆ isBool()

bool QJsonValue::isBool ( ) const
inline

Returns true if the value contains a boolean.

See also
toBool()

Definition at line 72 of file qjsonvalue.h.

Referenced by readInputFile().

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◆ isDouble()

bool QJsonValue::isDouble ( ) const
inline

Returns true if the value contains a double.

See also
toDouble()

Definition at line 73 of file qjsonvalue.h.

References Double.

Referenced by TileProvider::onNetworkReplyFinished(), operator==(), and QGeoRouteParserOsrmV5Private::parseReply().

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◆ isNull()

bool QJsonValue::isNull ( ) const
inline

Returns true if the value is null.

Definition at line 71 of file qjsonvalue.h.

References Null.

Referenced by exportFeature().

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◆ isObject()

bool QJsonValue::isObject ( ) const
inline

Returns true if the value contains an object.

See also
toObject()

Definition at line 76 of file qjsonvalue.h.

Referenced by operator[](), operator[](), QMapboxCommon::parseGeoLocation(), QGeoRouteParserOsrmV5Private::parseReply(), readInputFile(), readInputFileDirectory(), and toObject().

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◆ isString()

bool QJsonValue::isString ( ) const
inline

Returns true if the value contains a string.

See also
toString()

Definition at line 74 of file qjsonvalue.h.

Referenced by matches(), TileProvider::onNetworkReplyFinished(), readInputFile(), and readInputFileDirectory().

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◆ isUndefined()

bool QJsonValue::isUndefined ( ) const
inline

Returns true if the value is undefined.

This can happen in certain error cases as e.g. accessing a non existing key in a QJsonObject.

Definition at line 77 of file qjsonvalue.h.

References Undefined.

Referenced by readInputFile(), and readInputFileDirectory().

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◆ operator!=()

bool QJsonValue::operator!= ( const QJsonValue other) const

Returns true if the value is not equal to other.

Definition at line 862 of file qjsonvalue.cpp.

References other().

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◆ operator=() [1/2]

QJsonValue & QJsonValue::operator= ( const QJsonValue other)
noexcept

Assigns the value stored in other to this object.

Definition at line 256 of file qjsonvalue.cpp.

References copy(), other(), and swap().

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◆ operator=() [2/2]

QJsonValue & QJsonValue::operator= ( QJsonValue &&  other)
inlinenoexcept
Since
5.10

Move-assigns other to this value.

Definition at line 59 of file qjsonvalue.h.

References other(), and swap().

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◆ operator==()

bool QJsonValue::operator== ( const QJsonValue other) const

Returns true if the value is equal to other.

Definition at line 826 of file qjsonvalue.cpp.

References QCborValue::Array, QCborValue::Double, QCborValue::False, QCborValue::Integer, isDouble(), QCborValue::Map, QCborValue::Null, other(), QCborValue::String, toArray(), toDouble(), toObject(), toString(), QCborValue::True, QCborValue::Undefined, and QJsonPrivate::Value::valueHelper().

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◆ operator[]() [1/4]

const QJsonValue QJsonValue::operator[] ( const QString key) const

Returns a QJsonValue representing the value for the key key.

Equivalent to calling toObject().value(key).

The returned QJsonValue is QJsonValue::Undefined if the key does not exist, or if isObject() is false.

Since
5.10
See also
QJsonValue, QJsonValue::isUndefined(), QJsonObject

Definition at line 774 of file qjsonvalue.cpp.

◆ operator[]() [2/4]

const QJsonValue QJsonValue::operator[] ( QLatin1StringView  key) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since
5.10

Definition at line 795 of file qjsonvalue.cpp.

References isObject(), toObject(), Undefined, and QJsonObject::value().

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◆ operator[]() [3/4]

const QJsonValue QJsonValue::operator[] ( qsizetype  i) const

Returns a QJsonValue representing the value for index i.

Equivalent to calling toArray().at(i).

The returned QJsonValue is QJsonValue::Undefined, if i is out of bounds, or if isArray() is false.

Since
5.10
See also
QJsonValue, QJsonValue::isUndefined(), QJsonArray

Definition at line 815 of file qjsonvalue.cpp.

References QJsonArray::at(), i, isArray(), toArray(), and Undefined.

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◆ operator[]() [4/4]

const QJsonValue QJsonValue::operator[] ( QStringView  key) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since
5.14

Definition at line 783 of file qjsonvalue.cpp.

References isObject(), toObject(), Undefined, and QJsonObject::value().

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◆ swap()

void QJsonValue::swap ( QJsonValue other)
noexcept
Since
5.10

Swaps the value other with this. This operation is very fast and never fails.

Definition at line 269 of file qjsonvalue.cpp.

References other().

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◆ toArray() [1/2]

QJsonArray QJsonValue::toArray ( ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Converts the value to an array and returns it.

If type() is not Array, a \l{QJsonArray::}{QJsonArray()} will be returned.

Definition at line 727 of file qjsonvalue.cpp.

References QJsonArray, and toArray().

Referenced by QSSGQmlUtilities::applyEdit(), constructRoute(), QDefaultOutputMapping::load(), matches(), operator==(), operator[](), QT_BEGIN_NAMESPACE::parseDocument(), QMapboxCommon::parseGeoLocation(), QGeoRouteParserOsrmV4Private::parseReply(), QGeoRouteParserOsrmV5Private::parseStep(), readGpuFeatures(), readInputFile(), toArray(), QJsonValueConstRef::toArray(), and toVariant().

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◆ toArray() [2/2]

QJsonArray QJsonValue::toArray ( const QJsonArray defaultValue) const

Converts the value to an array and returns it.

If type() is not Array, the defaultValue will be returned.

Definition at line 707 of file qjsonvalue.cpp.

References QJsonPrivate::Value::container(), isArray(), Q_ASSERT, QJsonArray, and QJsonPrivate::Value::valueHelper().

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◆ toBool()

bool QJsonValue::toBool ( bool  defaultValue = false) const

Converts the value to a bool and returns it.

If type() is not bool, the defaultValue will be returned.

Definition at line 606 of file qjsonvalue.cpp.

References QCborValue::False, and QCborValue::True.

Referenced by readInputFile().

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◆ toDouble()

double QJsonValue::toDouble ( double  defaultValue = 0) const

Converts the value to a double and returns it.

If type() is not Double, the defaultValue will be returned.

Definition at line 675 of file qjsonvalue.cpp.

Referenced by constructRoute(), instructionDepart(), TileProvider::onNetworkReplyFinished(), operator==(), parseCoordinate(), QMapboxCommon::parseGeoLocation(), QT_BEGIN_NAMESPACE::parseLocation(), QGeoRouteParserOsrmV5Private::parseStep(), toInt(), toInteger(), and toVariant().

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◆ toInt()

int QJsonValue::toInt ( int  defaultValue = 0) const
Since
5.2 Converts the value to an int and returns it.

If type() is not Double or the value is not a whole number, the defaultValue will be returned.

Definition at line 625 of file qjsonvalue.cpp.

References QCborValue::Double, QCborValue::Integer, and toDouble().

Referenced by instructionRotary(), instructionRoundabout(), and V4CommandHandler::requestSequenceNr().

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◆ toInteger()

qint64 QJsonValue::toInteger ( qint64  defaultValue = 0) const
Since
6.0 Converts the value to an integer and returns it.

If type() is not Double or the value is not a whole number representable as qint64, the defaultValue will be returned.

Definition at line 653 of file qjsonvalue.cpp.

References QCborValue::Double, QCborValue::Integer, and toDouble().

Referenced by toVariant().

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◆ toObject() [1/2]

QJsonObject QJsonValue::toObject ( ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Converts the value to an object and returns it.

If type() is not Object, the \l {QJsonObject::}{QJsonObject()} will be returned.

Definition at line 757 of file qjsonvalue.cpp.

References QJsonObject, and toObject().

Referenced by GeoRouteJsonParserEsri::GeoRouteJsonParserEsri(), QDefaultOutputMapping::load(), QGtk3Json::load(), QKmsScreenConfig::loadConfig(), QGeoTiledMappingManagerEngineNokia::loadCopyrightsDescriptorsFromJson(), operator==(), operator[](), operator[](), CategoryParser::parse(), parseAddressObject(), parseCategories(), parseContactDetails(), QT_BEGIN_NAMESPACE::parseDocument(), QT_BEGIN_NAMESPACE::parseLocation(), QT_BEGIN_NAMESPACE::parsePlaceResult(), QGeoRouteParserOsrmV5Private::parseReply(), QGeoRouteParserOsrmV4Private::parseReply(), parseReview(), QGeoRouteParserOsrmV5Private::parseStep(), readInputFile(), readInputFileDirectory(), QOffscreenIntegration::setConfiguration(), toObject(), QJsonValueConstRef::toObject(), and toVariant().

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◆ toObject() [2/2]

QJsonObject QJsonValue::toObject ( const QJsonObject defaultValue) const

Converts the value to an object and returns it.

If type() is not Object, the defaultValue will be returned.

Definition at line 737 of file qjsonvalue.cpp.

References QJsonPrivate::Value::container(), isObject(), Q_ASSERT, QJsonObject, and QJsonPrivate::Value::valueHelper().

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◆ toString() [1/2]

◆ toString() [2/2]

QString QJsonValue::toString ( const QString defaultValue) const

Converts the value to a QString and returns it.

If type() is not String, the defaultValue will be returned.

Definition at line 685 of file qjsonvalue.cpp.

◆ toVariant()

QVariant QJsonValue::toVariant ( ) const

Converts the value to a \l {QVariant::}{QVariant()}.

The QJsonValue types will be converted as follows:

\value Null QMetaType::Nullptr \value Bool QMetaType::Bool \value Double QMetaType::Double or QMetaType::LongLong \value String QString \value Array QVariantList \value Object QVariantMap \value Undefined \l {QVariant::}{QVariant()}

See also
fromVariant()

Definition at line 548 of file qjsonvalue.cpp.

References QCborValue::Array, QCborValue::Double, QCborValue::False, QVariant::fromValue(), QCborValue::Integer, QCborValue::Map, QCborValue::Null, QCborValue::String, toArray(), toDouble(), toInteger(), toObject(), toString(), QJsonArray::toVariantList(), QJsonObject::toVariantMap(), QCborValue::True, and QCborValue::Undefined.

Referenced by QGeoRouteParserOsrmV5Private::parseStep(), and QJsonValueConstRef::toVariant().

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◆ type()

QJsonValue::Type QJsonValue::type ( ) const

Returns the type of the value.

See also
QJsonValue::Type

Definition at line 596 of file qjsonvalue.cpp.

References convertFromCborType().

Referenced by matches().

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Friends And Related Symbol Documentation

◆ operator<< [1/2]

Q_CORE_EXPORT QDataStream & operator<< ( QDataStream ,
const QJsonValue  
)
friend

Definition at line 1146 of file qjsonvalue.cpp.

◆ operator<< [2/2]

Q_CORE_EXPORT QDebug operator<< ( QDebug  ,
const QJsonValue  
)
friend

Definition at line 1105 of file qjsonvalue.cpp.

◆ QCborValue

friend class QCborValue
friend

Definition at line 104 of file qjsonvalue.h.

◆ QJsonArray

friend class QJsonArray
friend

Definition at line 102 of file qjsonvalue.h.

Referenced by toArray(), and toArray().

◆ QJsonObject

friend class QJsonObject
friend

Definition at line 103 of file qjsonvalue.h.

Referenced by toObject(), and toObject().

◆ QJsonPrivate::Value

friend class QJsonPrivate::Value
friend

Definition at line 101 of file qjsonvalue.h.


The documentation for this class was generated from the following files: