QVersionNumber Class

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

Member Function Documentation

QVersionNumber::QVersionNumber()

Produces a null version.

See also isNull().

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

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

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

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

This constructor is only enabled if the compiler supports C++11 move semantics.

QVersionNumber::QVersionNumber(int args)

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

This constructor is only enabled if the compiler supports C++11 initializer lists.

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, int min, int mic)

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

[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 segement 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().