QtCore.QUuid Class Reference

The QUuid class stores a Universally Unique Identifier (UUID). More...

Inheritance diagram for QtCore.QUuid:

Collaboration diagram for QtCore.QUuid:

Public Types
enum	Variant {   DCE = 2, Microsoft = 6, NCS = 0, Reserved = 7,   VarUnknown = -1 }
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enum	Version {   EmbeddedPOSIX = 2, Name = 3, Random = 4, Time = 1,   VerUnknown = -1 }
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Public Member Functions
override bool	Equals (object o)
override int	GetHashCode ()
	QUuid ()
	QUuid (QByteArray arg1)
	QUuid (QUuid copy)
	QUuid (string arg1)
	QUuid (uint l, ushort w1, ushort w2, byte b1, byte b2, byte b3, byte b4, byte b5, byte b6, byte b7, byte b8)
virtual void	CreateProxy ()
new bool	IsNull ()
new QByteArray	ToByteArray ()
new QByteArray	ToRfc4122 ()
override string	ToString ()
new QUuid.Variant	variant ()
new QUuid.Version	version ()
new void	Dispose ()

Static Public Member Functions
static QUuid	CreateUuid ()
static QUuid	FromRfc4122 (QByteArray arg1)
static	operator System.String (QUuid arg1)
static bool	operator!= (QUuid arg1, QUuid arg2)
static bool	operator< (QUuid arg1, QUuid arg2)
static bool	operator== (QUuid arg1, QUuid arg2)
static bool	operator> (QUuid arg1, QUuid arg2)

Protected Member Functions
	QUuid (System.Type dummy)

Protected Attributes
SmokeInvocation	interceptor

Properties
virtual System.IntPtr	SmokeObject [get, set]

Detailed Description

The QUuid class stores a Universally Unique Identifier (UUID).

Using Universally Unique IDentifiers (UUID) is a standard way to uniquely identify entities in a distributed computing environment. A UUID is a 16-byte (128-bit) number generated by some algorithm that is meant to guarantee that the UUID will be unique in the distributed computing environment where it is used. The acronym GUID is often used instead, Globally Unique IDentifiers, but it refers to the same thing.

Actually, the GUID is one variant of UUID. Multiple variants are in use. Each UUID contains a bit field that specifies which type (variant) of UUID it is. Call variant() to discover which type of UUID an instance of QUuid contains. It extracts the three most signifcant bits of byte 8 of the 16 bytes. In QUuid, byte 8 is QUuid::data4[0]. If you create instances of QUuid using the constructor that accepts all the numeric values as parameters, use the following table to set the three most significant bits of parameter b1, which becomes QUuid::data4[0] and contains the variant field in its three most significant bits. In the table, 'x' means don't care.

msb0msb1msb2Variant

0 x x NCS (Network Computing System)

1 0 x DCE (Distributed Computing Environment)

1 1 0 Microsoft (GUID)

1 1 1 Reserved for future expansion

If variant() returns QUuid::DCE, the UUID also contains a version field in the four most significant bits of QUuid::data3, and you can call version() to discover which version your QUuid contains. If you create instances of QUuid using the constructor that accepts all the numeric values as parameters, use the following table to set the four most significant bits of parameter w2, which becomes QUuid::data3 and contains the version field in its four most significant bits.

msb0msb1msb2msb3Version

0 0 0 1 Time

0 0 1 0 Embedded POSIX

0 0 1 1 Name

0 1 0 0 Random

The field layouts for the DCE versions listed in the table above are specified in the Network Working Group UUID Specification.

Most platforms provide a tool for generating new UUIDs, e.g. uuidgen and guidgen. You can also use createUuid(). UUIDs generated by createUuid() are of the random type. Their QUuid::Version bits are set to QUuid::Random, and their QUuid::Variant bits are set to QUuid::DCE. The rest of the UUID is composed of random numbers. Theoretically, this means there is a small chance that a UUID generated by createUuid() will not be unique. But it is a very small chance.

UUIDs can be constructed from numeric values or from strings, or using the static createUuid() function. They can be converted to a string with toString(). UUIDs have a variant() and a version(), and null UUIDs return true from isNull().

Member Enumeration Documentation

enum QtCore.QUuid.Variant

This enum defines the values used in the variant field of the UUID. The value in the variant field determines the layout of the 128-bit value.

Enumerator:

DCE	Distributed Computing Environment, the scheme used by QUuid
Microsoft	Reserved for Microsoft backward compatibility (GUID)
NCS	Reserved for NCS (Network Computing System) backward compatibility
Reserved	Reserved for future definition
VarUnknown	Variant is unknown

enum QtCore.QUuid.Version

This enum defines the values used in the version field of the UUID. The version field is meaningful only if the value in the variant field is QUuid::DCE.

Enumerator:

EmbeddedPOSIX	DCE Security version, with embedded POSIX UUIDs
Name	Name-based, by using values from a name for all sections
Random	Random-based, by using random numbers for all sections
Time	Time-based, by using timestamp, clock sequence, and MAC network card address (if available) for the node sections
VerUnknown	Version is unknown

Constructor & Destructor Documentation

QtCore.QUuid.QUuid ( System.Type  dummy )

protected

QtCore.QUuid.QUuid

(

)

Creates the null UUID. toString() will output the null UUID as "{00000000-0000-0000-0000-000000000000}".

QtCore.QUuid.QUuid

(

QByteArray

arg1

)

Creates a QUuid object from the QByteArray text, which must be formatted as five hex fields separated by '-', e.g., "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}" where 'x' is a hex digit. The curly braces shown here are optional, but it is normal to include them. If the conversion fails, a null UUID is created. See toByteArray() for an explanation of how the five hex fields map to the public data members in QUuid.

This function was introduced in Qt 4.8.

See also toByteArray() and QUuid().

QtCore.QUuid.QUuid

(

QUuid

copy

)

Creates the null UUID. toString() will output the null UUID as "{00000000-0000-0000-0000-000000000000}".

QtCore.QUuid.QUuid

(

string

arg1

)

Creates a QUuid object from the string text, which must be formatted as five hex fields separated by '-', e.g., "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}" where 'x' is a hex digit. The curly braces shown here are optional, but it is normal to include them. If the conversion fails, a null UUID is created. See toString() for an explanation of how the five hex fields map to the public data members in QUuid.

See also toString() and QUuid().

QtCore.QUuid.QUuid	(	uint	l,
		ushort	w1,
		ushort	w2,
		byte	b1,
		byte	b2,
		byte	b3,
		byte	b4,
		byte	b5,
		byte	b6,
		byte	b7,
		byte	b8
	)

Creates the null UUID. toString() will output the null UUID as "{00000000-0000-0000-0000-000000000000}".

Member Function Documentation

virtual void QtCore.QUuid.CreateProxy ( )

virtual

static QUuid QtCore.QUuid.CreateUuid ( )

static

On any platform other than Windows, this function returns a new UUID with variant QUuid::DCE and version QUuid::Random. If the /dev/urandom device exists, then the numbers used to construct the UUID will be of cryptographic quality, which will make the UUID unique. Otherwise, the numbers of the UUID will be obtained from the local pseudo-random number generator (qrand(), which is seeded by qsrand()) which is usually not of cryptograhic quality, which means that the UUID can't be guaranteed to be unique.

On a Windows platform, a GUID is generated, which almost certainly will be unique, on this or any other system, networked or not.

See also variant() and version().

new void QtCore.QUuid.Dispose

(

)

override bool QtCore.QUuid.Equals

(

object

o

)

static QUuid QtCore.QUuid.FromRfc4122 ( QByteArray  arg1 )

static

Creates a QUuid object from the binary representation of the UUID given by bytes, as specified by RFC 4122 section 4.1.2. See toRfc4122() for a further explanation of the order of bytes required.

The byte array accepted is not a human readable format.

If the conversion fails, a null UUID is created.

This function was introduced in Qt 4.8.

See also toRfc4122() and QUuid().

override int QtCore.QUuid.GetHashCode

(

)

new bool QtCore.QUuid.IsNull

(

)

Returns true if this is the null UUID {00000000-0000-0000-0000-000000000000}; otherwise returns false.

static QtCore.QUuid.operator System.String ( QUuid  arg1 )

explicitstatic

Returns the string representation of the uuid.

See also toString().

static bool QtCore.QUuid.operator!= ( QUuid  arg1, QUuid  arg2  )

static

Returns true if this QUuid and the other QUuid are different; otherwise returns false.

static bool QtCore.QUuid.operator< ( QUuid  arg1, QUuid  arg2  )

static

Returns true if this QUuid has the same variant field as the other QUuid and is lexicographically before the other QUuid. If the other QUuid has a different variant field, the return value is determined by comparing the two variants.

See also variant().

static bool QtCore.QUuid.operator== ( QUuid  arg1, QUuid  arg2  )

static

Returns true if this QUuid and the other QUuid are identical; otherwise returns false.

static bool QtCore.QUuid.operator> ( QUuid  arg1, QUuid  arg2  )

static

Returns true if this QUuid has the same variant field as the other QUuid and is lexicographically after the other QUuid. If the other QUuid has a different variant field, the return value is determined by comparing the two variants.

See also variant().

new QByteArray QtCore.QUuid.ToByteArray

(

)

Returns the binary representation of this QUuid. The byte array is formatted as five hex fields separated by '-' and enclosed in curly braces, i.e., "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}" where 'x' is a hex digit. From left to right, the five hex fields are obtained from the four public data members in QUuid as follows:

Field #Source

1 data1

2 data2

3 data3

4 data4[0] .. data4[1]

5 data4[2] .. data4[7]

This function was introduced in Qt 4.8.

new QByteArray QtCore.QUuid.ToRfc4122

(

)

Returns the binary representation of this QUuid. The byte array is in big endian format, and formatted according to RFC 4122, section 4.1.2 - "Layout and byte order".

The order is as follows:

Field #Source

1 data1

2 data2

3 data3

4 data4[0] .. data4[7]

This function was introduced in Qt 4.8.

override string QtCore.QUuid.ToString

(

)

Returns the string representation of this QUuid. The string is formatted as five hex fields separated by '-' and enclosed in curly braces, i.e., "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}" where 'x' is a hex digit. From left to right, the five hex fields are obtained from the four public data members in QUuid as follows:

Field #Source

1 data1

2 data2

3 data3

4 data4[0] .. data4[1]

5 data4[2] .. data4[7]

new QUuid.Variant QtCore.QUuid.variant

(

)

Returns the value in the variant field of the UUID. If the return value is QUuid::DCE, call version() to see which layout it uses. The null UUID is considered to be of an unknown variant.

See also version().

new QUuid.Version QtCore.QUuid.version

(

)

Returns the version field of the UUID, if the UUID's variant field is QUuid::DCE. Otherwise it returns QUuid::VerUnknown.

See also variant().

Member Data Documentation

SmokeInvocation QtCore.QUuid.interceptor

protected

Property Documentation

virtual System.IntPtr QtCore.QUuid.SmokeObject

getset