- Qt 5.15
- Qt Core
- C++ Classes
- QVersionNumber
- Qt 5.15.18 Reference Documentation

# QVersionNumber Class

The QVersionNumber class contains a version number with an arbitrary number of segments. More...

Header: | #include <QVersionNumber>
qmake: | QT += core
Since: | Qt 5.6

This class was introduced in Qt 5.6.

- List of all members, including inherited members

## Public Functions

| QVersionNumber(int maj, int min, int mic)
| QVersionNumber(int maj, int min)
| QVersionNumber(int maj)
| QVersionNumber(std::initializer_list<int> args)
| QVersionNumber(QVector<int> &&seg)
| QVersionNumber(const QVector<int> &seg)
| QVersionNumber()
bool | isNormalized() const
bool | isNull() const
bool | isPrefixOf(const QVersionNumber &other) const
int | majorVersion() const
int | microVersion() const
int | minorVersion() const
QVersionNumber | normalized() const
int | segmentAt(int index) const
int | segmentCount() const
QVector<int> | segments() const
QString | toString() const

## Static Public Members

QVersionNumber | commonPrefix(const QVersionNumber &v1, const QVersionNumber &v2)
int | compare(const QVersionNumber &v1, const QVersionNumber &v2)
QVersionNumber | fromString(const QString &string, int *suffixIndex = nullptr)
QVersionNumber | fromString(QLatin1String string, int *suffixIndex = nullptr)
QVersionNumber | fromString(QStringView string, int *suffixIndex = nullptr)

## Related Non-Members

bool | operator!=(const QVersionNumber &lhs, const QVersionNumber &rhs)
bool | operator<(const QVersionNumber &lhs, const QVersionNumber &rhs)
QDataStream & | operator<<(QDataStream &out, const QVersionNumber &version)
bool | operator<=(const QVersionNumber &lhs, const QVersionNumber &rhs)
bool | operator==(const QVersionNumber &lhs, const QVersionNumber &rhs)
bool | operator>(const QVersionNumber &lhs, const QVersionNumber &rhs)
bool | operator>=(const QVersionNumber &lhs, const QVersionNumber &rhs)
QDataStream & | operator>>(QDataStream &in, QVersionNumber &version)

## Detailed Description

     QVersionNumber version(1, 2, 3);  // 1.2.3

## Member Function Documentation

### QVersionNumber::QVersionNumber(int maj, int min, int mic)

Constructs a QVersionNumber consisting of the major, minor, and micro version numbers maj, min and mic, respectively.

### QVersionNumber::QVersionNumber(int maj, int min)

Constructs a QVersionNumber consisting of the major and minor version numbers maj and min, respectively.

### QVersionNumber::QVersionNumber(int maj)

Constructs a QVersionNumber consisting of just the major version number maj.

### QVersionNumber::QVersionNumber(std::initializer_list<int> args)

Constructs a version number from the std::initializer_list specified by args.

### QVersionNumber::QVersionNumber(QVector<int> &&seg)

Move-constructs a version number from the list of numbers contained in seg.

### QVersionNumber::QVersionNumber(const QVector<int> &seg)

Constructs a version number from the list of numbers contained in seg.

### QVersionNumber::QVersionNumber()

Produces a null version.

See also isNull().

### `[static]` QVersionNumber QVersionNumber::commonPrefix(const QVersionNumber &v1, const QVersionNumber &v2)

QVersionNumber QVersionNumber::commonPrefix(const QVersionNumber &v1, const QVersionNumber &v2)

Returns a version number that is a parent version of both v1 and v2.

See also isPrefixOf().

### `[static]` int QVersionNumber::compare(const QVersionNumber &v1, const QVersionNumber &v2)

Compares v1 with v2 and returns an integer less than, equal to, or greater than zero, depending on whether v1 is less than, equal to, or greater than v2, respectively.

Comparisons are performed by comparing the segments of v1 and v2 starting at index 0 and working towards the end of the longer list.

     QVersionNumber v1(1, 2);
     QVersionNumber v2(1, 2, 0);
     int compare = QVersionNumber::compare(v1, v2); // compare == -1

### `[static]` QVersionNumber QVersionNumber::fromString(const QString &string, int *suffixIndex = nullptr)

Constructs a QVersionNumber from a specially formatted string of non-negative decimal numbers delimited by a period (`.`).

Once the numerical segments have been parsed, the remainder of the string is considered to be the suffix string. The start index of that string will be stored in suffixIndex if it is not null.

     QString string("5.4.0-alpha");
     int suffixIndex;
     QVersionNumber version = QVersionNumber::fromString(string, &suffixIndex);
     // version is 5.4.0
     // suffixIndex is 5

See also isNull().

### `[static]` QVersionNumber QVersionNumber::fromString(QLatin1String string, int *suffixIndex = nullptr)

This is an overloaded function.

Constructs a QVersionNumber from a specially formatted string of non-negative decimal numbers delimited by '.'.

Once the numerical segments have been parsed, the remainder of the string is considered to be the suffix string. The start index of that string will be stored in suffixIndex if it is not null.

     QLatin1String string("5.4.0-alpha");
     int suffixIndex;
     auto version = QVersionNumber::fromString(string, &suffixIndex);
     // version is 5.4.0
     // suffixIndex is 5

This function was introduced in Qt 5.10.

See also isNull().

### `[static]` QVersionNumber QVersionNumber::fromString(QStringView string, int *suffixIndex = nullptr)

This is an overloaded function.

Constructs a QVersionNumber from a specially formatted string of non-negative decimal numbers delimited by '.'.

Once the numerical segments have been parsed, the remainder of the string is considered to be the suffix string. The start index of that string will be stored in suffixIndex if it is not null.

     QString string("5.4.0-alpha");
     int suffixIndex;
     QVersionNumber version = QVersionNumber::fromString(string, &suffixIndex);
     // version is 5.4.0
     // suffixIndex is 5

This function was introduced in Qt 5.10.

See also isNull().

### bool QVersionNumber::isNormalized() const

Returns `true` if the version number does not contain any trailing zeros, otherwise returns `false`.

See also normalized().

### bool QVersionNumber::isNull() const

Returns `true` if there are zero numerical segments, otherwise returns `false`.

See also segments().

### bool QVersionNumber::isPrefixOf(const QVersionNumber &other) const

Returns `true` if the current version number is contained in the other version number, otherwise returns `false`.

     QVersionNumber v1(5, 3);
     QVersionNumber v2(5, 3, 1);
     bool value = v1.isPrefixOf(v2); // true

See also commonPrefix().

### int QVersionNumber::majorVersion() const

Returns the major version number, that is, the first segment. This function is equivalent to segmentAt(0). If this QVersionNumber object is null, this function returns 0.

See also isNull() and segmentAt().

### int QVersionNumber::microVersion() const

Returns the micro version number, that is, the third segment. This function is equivalent to segmentAt(2). If this QVersionNumber object does not contain a micro number, this function returns 0.

See also isNull() and segmentAt().

### int QVersionNumber::minorVersion() const

Returns the minor version number, that is, the second segment. This function is equivalent to segmentAt(1). If this QVersionNumber object does not contain a minor number, this function returns 0.

See also isNull() and segmentAt().

### QVersionNumber QVersionNumber::normalized() const

Returns an equivalent version number but with all trailing zeros removed.

To check if two numbers are equivalent, use normalized() on both version numbers before performing the compare.

     QVersionNumber v1(5, 4);
     QVersionNumber v2(5, 4, 0);
     bool equivalent = v1.normalized() == v2.normalized();
     bool equal = v1 == v2;
     // equivalent is true
     // equal is false

### int QVersionNumber::segmentAt(int index) const

Returns the segment value at index. If the index does not exist, returns 0.

See also segments() and segmentCount().

### int QVersionNumber::segmentCount() const

Returns the number of integers stored in segments().

See also segments().

### QVector<int> QVersionNumber::segments() const

Returns all of the numerical segments.

See also majorVersion(), minorVersion(), and microVersion().

### QString QVersionNumber::toString() const

Returns a string with all of the segments delimited by a period (`.`).

See also majorVersion(), minorVersion(), microVersion(), and segments().

## Related Non-Members

### bool operator!=(const QVersionNumber &lhs, const QVersionNumber &rhs)

Returns `true` if lhs is not equal to rhs; otherwise returns `false`.

See also QVersionNumber::compare().

### bool operator<(const QVersionNumber &lhs, const QVersionNumber &rhs)

Returns `true` if lhs is less than rhs; otherwise returns `false`.

See also QVersionNumber::compare().

### QDataStream &operator<<(QDataStream &out, const QVersionNumber &version)

Writes the version number version to stream out.

Note that this has nothing to do with QDataStream::version().

### bool operator<=(const QVersionNumber &lhs, const QVersionNumber &rhs)

Returns `true` if lhs is less than or equal to rhs; otherwise returns `false`.

See also QVersionNumber::compare().

### bool operator==(const QVersionNumber &lhs, const QVersionNumber &rhs)

Returns `true` if lhs is equal to rhs; otherwise returns `false`.

See also QVersionNumber::compare().

### bool operator>(const QVersionNumber &lhs, const QVersionNumber &rhs)

Returns `true` if lhs is greater than rhs; otherwise returns `false`.

See also QVersionNumber::compare().

### bool operator>=(const QVersionNumber &lhs, const QVersionNumber &rhs)

Returns `true` if lhs is greater than or equal to rhs; otherwise returns `false`.

See also QVersionNumber::compare().

### QDataStream &operator>>(QDataStream &in, QVersionNumber &version)

Reads a version number from stream in and stores it in version.

Note that this has nothing to do with QDataStream::version().