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Qt
Internal/Contributor docs for the Qt SDK. Note: These are NOT official API docs; those are found at https://doc.qt.io/
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Qt
Internal/Contributor docs for the Qt SDK. Note: These are NOT official API docs; those are found at https://doc.qt.io/
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\inmodule QtCore More...
#include <quuid.h>
Inheritance diagram for QUuid: Collaboration diagram for QUuid:Classes | |
| class | Id128Bytes |
| \inmodule QtCore More... | |
Public Types | |
| enum | Variant { VarUnknown =-1 , NCS = 0 , DCE = 2 , Microsoft = 6 , Reserved = 7 } |
| This enum defines the values used in the \l{Variant field} {variant field} of the UUID. More... | |
| enum | Version { VerUnknown =-1 , Time = 1 , EmbeddedPOSIX = 2 , Md5 = 3 , Name = Md5 , Random = 4 , Sha1 = 5 , UnixEpoch = 7 } |
| This enum defines the values used in the \l{Version field} {version field} of the UUID. More... | |
| enum | StringFormat { WithBraces = 0 , WithoutBraces = 1 , Id128 = 3 } |
Public Member Functions | |
| constexpr | QUuid () noexcept |
| Creates the null UUID. | |
| constexpr | QUuid (uint l, ushort w1, ushort w2, uchar b1, uchar b2, uchar b3, uchar b4, uchar b5, uchar b6, uchar b7, uchar b8) noexcept |
| Creates a UUID with the value specified by the parameters, l, w1, w2, b1, b2, b3, b4, b5, b6, b7, b8. | |
| QUuid (Id128Bytes id128, QSysInfo::Endian order=QSysInfo::BigEndian) noexcept | |
| QUuid (QAnyStringView string) noexcept | |
| 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 each 'x' is a hex digit. | |
| QString | toString (StringFormat mode=WithBraces) const |
| QByteArray | toByteArray (StringFormat mode=WithBraces) const |
| Id128Bytes | toBytes (QSysInfo::Endian order=QSysInfo::BigEndian) const noexcept |
| QByteArray | toRfc4122 () const |
| Returns the binary representation of this QUuid. | |
| constexpr bool | isNull (QT6_DECL_NEW_OVERLOAD) const noexcept |
Returns true if this is the null UUID {00000000-0000-0000-0000-000000000000}; otherwise returns false. | |
| constexpr Variant | variant (QT6_DECL_NEW_OVERLOAD) const noexcept |
| Returns the value in the \l{Variant field} {variant field} of the UUID. | |
| constexpr Version | version (QT6_DECL_NEW_OVERLOAD) const noexcept |
| Returns the \l{Version field} {version field} of the UUID, if the UUID's \l{Variant field} {variant field} is QUuid::DCE. | |
Static Public Member Functions | |
| static QUuid | fromString (QAnyStringView string) noexcept |
| static QUuid | fromBytes (const void *bytes, QSysInfo::Endian order=QSysInfo::BigEndian) |
| static QUuid | fromRfc4122 (QByteArrayView) noexcept |
| Creates a QUuid object from the binary representation of the UUID, as specified by RFC 4122 section 4.1.2. | |
| static QUuid | createUuid () |
| On any platform other than Windows, this function returns a new UUID with variant QUuid::DCE and version QUuid::Random. | |
| static QUuid | createUuidV5 (QUuid ns, QByteArrayView baseData) noexcept |
| static QUuid | createUuidV3 (QUuid ns, QByteArrayView baseData) noexcept |
| static Q_WEAK_OVERLOAD QUuid | createUuidV3 (const QUuid &ns, const QString &baseData) |
| static Q_WEAK_OVERLOAD QUuid | createUuidV5 (const QUuid &ns, const QString &baseData) |
| static QUuid | createUuidV7 () |
Public Attributes | |
| uint | data1 |
| ushort | data2 |
| ushort | data3 |
| uchar | data4 [8] |
Friends | |
| constexpr bool | comparesEqual (const QUuid &lhs, const QUuid &rhs) noexcept |
| constexpr Qt::strong_ordering | compareThreeWay (const QUuid &lhs, const QUuid &rhs) noexcept |
Related Symbols | |
(Note that these are not member symbols.) | |
| QUuid::Id128Bytes | qFromBigEndian (QUuid::Id128Bytes src) |
| QUuid::Id128Bytes | qFromLittleEndian (QUuid::Id128Bytes src) |
| QUuid::Id128Bytes | qToBigEndian (QUuid::Id128Bytes src) |
| QUuid::Id128Bytes | qToLittleEndian (QUuid::Id128Bytes src) |
| QDataStream & | operator<< (QDataStream &s, const QUuid &id) |
| Writes the UUID id to the data stream s. | |
| QDataStream & | operator>> (QDataStream &s, QUuid &id) |
| Reads a UUID from the stream s into id. | |
| QDebug | operator<< (QDebug dbg, const QUuid &id) |
| Writes the UUID id to the output stream for debugging information dbg. | |
\inmodule QtCore
The QUuid class stores a Universally Unique Identifier (UUID).
\reentrant
\compares strong \compareswith strong GUID
Using {U}niversally {U}nique {ID}entifiers (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, {G}lobally {U}nique {ID}entifiers, but it refers to the same thing.
\target Variant field 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 significant 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}.
\table \header
\row
\row
\row
\row
\endtable
\target Version field 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.
\table \header
\row
\row
\row
\row
\row
\endtable
The field layouts for the DCE versions listed in the table above are specified in the \l{RFC 4122} {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 \l{http://en.wikipedia.org/wiki/Universally_Unique_Identifier#Random_UUID_probability_of_duplicates} {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().
| enum QUuid::StringFormat |
This enum is used by toString(StringFormat) to control the formatting of the string representation. The possible values are:
\value WithBraces The default, toString() will return five hex fields, separated by dashes and surrounded by braces. Example: {00000000-0000-0000-0000-000000000000}. \value WithoutBraces Only the five dash-separated fields, without the braces. Example: 00000000-0000-0000-0000-000000000000. \value Id128 Only the hex digits, without braces or dashes. Note that QUuid cannot parse this back again as input.
| Enumerator | |
|---|---|
| WithBraces | |
| WithoutBraces | |
| Id128 | |
| enum QUuid::Variant |
This enum defines the values used in the \l{Variant field} {variant field} of the UUID.
The value in the variant field determines the layout of the 128-bit value.
\value VarUnknown Variant is unknown \value NCS Reserved for NCS (Network Computing System) backward compatibility \value DCE Distributed Computing Environment, the scheme used by QUuid \value Microsoft Reserved for Microsoft backward compatibility (GUID) \value Reserved Reserved for future definition
| Enumerator | |
|---|---|
| VarUnknown | |
| NCS | |
| DCE | |
| Microsoft | |
| Reserved | |
| enum QUuid::Version |
This enum defines the values used in the \l{Version field} {version field} of the UUID.
The version field is meaningful only if the value in the \l{Variant field} {variant field} is QUuid::DCE.
\value VerUnknown Version is unknown \value Time Time-based, by using timestamp, clock sequence, and MAC network card address (if available) for the node sections \value EmbeddedPOSIX DCE Security version, with embedded POSIX UUIDs \value Name Name-based, by using values from a name for all sections \value Md5 Alias for Name \value Random Random-based, by using random numbers for all sections \value Sha1 Name-based version that uses SHA-1 hashing \value UnixEpoch [since 6.9] Time-based UUID using the number of milliseconds since the UNIX epoch
| Enumerator | |
|---|---|
| VerUnknown | |
| Time | |
| EmbeddedPOSIX | |
| Md5 | |
| Name | |
| Random | |
| Sha1 | |
| UnixEpoch | |
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inlineconstexprnoexcept |
Creates the null UUID.
toString() will output the null UUID as "{00000000-0000-0000-0000-000000000000}".
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inlineexplicitnoexcept |
Creates a QUuid based on the integral id128 parameter. The input id128 parameter is considered to have byte order order.
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inlineexplicitnoexcept |
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 each '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.
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static |
On any platform other than Windows, this function returns a new UUID with variant QUuid::DCE and version QUuid::Random.
On Windows, a GUID is generated using the Windows API and will be of the type that the API decides to create.
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inlinestatic |
This function returns a new UUID with variant QUuid::DCE and version QUuid::Md5. ns is the namespace and baseData is the basic data as described by RFC 4122.
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staticnoexcept |
This function returns a new UUID with variant QUuid::DCE and version QUuid::Md5. ns is the namespace and baseData is the basic data as described by RFC 4122.
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inlinestatic |
This function returns a new UUID with variant QUuid::DCE and version QUuid::Sha1. ns is the namespace and baseData is the basic data as described by RFC 4122.
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staticnoexcept |
This function returns a new UUID with variant QUuid::DCE and version QUuid::Sha1. ns is the namespace and baseData is the basic data as described by RFC 4122.
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static |
This function returns a new UUID with variant QUuid::DCE and version QUuid::UnixEpoch.
It uses a time-ordered value field derived from the number of milliseconds since the UNIX Epoch as described by \l {https://datatracker.ietf.org/doc/html/rfc9562#name-uuid-version-7}{RFC9562}.
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inlinestatic |
Reads 128 bits (16 bytes) from bytes using byte order order and returns the QUuid corresponding to those bytes. This function does the same as fromRfc4122() if the byte order order is QSysInfo::BigEndian.
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staticnoexcept |
Creates a QUuid object from the binary representation of the UUID, 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.
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staticnoexcept |
Creates a QUuid object from the string string, which must be formatted as five hex fields separated by '-', e.g., "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}" where each '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 returned. See toString() for an explanation of how the five hex fields map to the public data members in QUuid.
|
inlineconstexprnoexcept |
| QByteArray QUuid::toByteArray | ( | QUuid::StringFormat | mode = WithBraces | ) | const |
Returns the string representation of this QUuid, with the formattiong controlled by the mode parameter. From left to right, the five hex fields are obtained from the four public data members in QUuid as follows:
\table \header
\row
\row
\row
\row
\row
\endtable
|
inlinenoexcept |
Returns a 128-bit ID created from this QUuid on the byte order specified by order. The binary content of this function is the same as toRfc4122() if the order is QSysInfo::BigEndian. See that function for more details.
| QByteArray QUuid::toRfc4122 | ( | ) | const |
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:
\table \header
\row
\row
\row
\row
\endtable
The bytes in the byte array returned by this function contains the same binary content as toBytes().
| QString QUuid::toString | ( | QUuid::StringFormat | mode = WithBraces | ) | const |
Returns the string representation of this QUuid, with the formattiong controlled by the mode parameter. From left to right, the five hex fields are obtained from the four public data members in QUuid as follows:
\table \header
\row
\row
\row
\row
\row
\endtable
|
inlineconstexprnoexcept |
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inlineconstexprnoexcept |
Returns the \l{Version field} {version field} of the UUID, if the UUID's \l{Variant field} {variant field} is QUuid::DCE.
Otherwise it returns QUuid::VerUnknown.
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friend |
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1.13.2