- Qt 6.9
- Qt Core
- C++ Classes
- QTime
- Qt 6.9.2 Reference Documentation

# QTime Class

The QTime class provides clock time functions. More...

Header: | `#include <QTime>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS Core)` `target_link_libraries(mytarget PRIVATE Qt6::Core)`
qmake: | `QT += core`

- List of all members, including inherited members

This class is strongly comparable.

Note: All functions in this class are reentrant.

## Public Functions

| QTime()
| QTime(int h, int m, int s = 0, int ms = 0)
QTime | addMSecs(int ms) const
QTime | addSecs(int s) const
int | hour() const
bool | isNull() const
bool | isValid() const
int | minute() const
int | msec() const
int | msecsSinceStartOfDay() const
int | msecsTo(QTime t) const
int | second() const
int | secsTo(QTime t) const
bool | setHMS(int h, int m, int s, int ms = 0)

## Static Public Members

QTime | currentTime()
QTime | fromMSecsSinceStartOfDay(int msecs)
bool | isValid(int h, int m, int s, int ms = 0)

## Related Non-Members

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

## Detailed Description

A QTime object contains a clock time, which it can express as the numbers of hours, minutes, seconds, and milliseconds since midnight. It provides functions for comparing times and for manipulating a time by adding a number of milliseconds. QTime objects should be passed by value rather than by reference to const; they simply package `int`.

QTime uses the 24-hour clock format; it has no concept of AM/PM. Unlike QDateTime, QTime knows nothing about time zones or daylight-saving time (DST).

A QTime object is typically created either by giving the number of hours, minutes, seconds, and milliseconds explicitly, or by using the static function currentTime(), which creates a QTime object that represents the system's local time.

The hour(), minute(), second(), and msec() functions provide access to the number of hours, minutes, seconds, and milliseconds of the time. The same information is provided in textual format by the toString() function.

The addSecs() and addMSecs() functions provide the time a given number of seconds or milliseconds later than a given time. Correspondingly, the number of seconds or milliseconds between two times can be found using secsTo() or msecsTo().

QTime provides a full set of operators to compare two QTime objects; an earlier time is considered smaller than a later one; if A.msecsTo(B) is positive, then A < B.

QTime objects can also be created from a text representation using fromString() and converted to a string representation using toString(). All conversion to and from string formats is done using the C locale. For localized conversions, see QLocale.

See also QDate and QDateTime.

## Member Function Documentation

### `[constexpr]` QTime::QTime()

Constructs a null time object. For a null time, isNull() returns `true` and isValid() returns `false`. If you need a zero time, use QTime(0, 0). For the start of a day, see QDate::startOfDay().

See also isNull() and isValid().

### QTime::QTime(int h, int m, int s = 0, int ms = 0)

Constructs a time with hour h, minute m, seconds s and milliseconds ms.

h must be in the range 0 to 23, m and s must be in the range 0 to 59, and ms must be in the range 0 to 999.

See also isValid().

### QTime QTime::addMSecs(int ms) const

Returns a QTime object containing a time ms milliseconds later than the time of this object (or earlier if ms is negative).

Note that the time will wrap if it passes midnight. See addSecs() for an example.

Returns a null time if this time is invalid.

See also addSecs(), msecsTo(), and QDateTime::addMSecs().

### QTime QTime::addSecs(int s) const

Returns a QTime object containing a time s seconds later than the time of this object (or earlier if s is negative).

Note that the time will wrap if it passes midnight.

Returns a null time if this time is invalid.

Example:

     QTime n(14, 0, 0);                // n == 14:00:00
     QTime t;
     t = n.addSecs(70);                // t == 14:01:10
     t = n.addSecs(-70);               // t == 13:58:50
     t = n.addSecs(10 * 60 * 60 + 5);  // t == 00:00:05
     t = n.addSecs(-15 * 60 * 60);     // t == 23:00:00

See also addMSecs(), secsTo(), and QDateTime::addSecs().

### `[static]` QTime QTime::currentTime()

Returns the current time as reported by the system clock.

Note that the accuracy depends on the accuracy of the underlying operating system; not all systems provide 1-millisecond accuracy.

Furthermore, currentTime() only increases within each day; it shall drop by 24 hours each time midnight passes; and, beside this, changes in it may not correspond to elapsed time, if a daylight-saving transition intervenes.

See also QDateTime::currentDateTime() and QDateTime::currentDateTimeUtc().

### `[static constexpr]` QTime QTime::fromMSecsSinceStartOfDay(int msecs)

Returns a new QTime instance with the time set to the number of msecs since the start of the day, i.e. since 00:00:00.

If msecs falls outside the valid range an invalid QTime will be returned.

See also msecsSinceStartOfDay().

### int QTime::hour() const

Returns the hour part (0 to 23) of the time.

Returns -1 if the time is invalid.

See also minute(), second(), and msec().

### `[constexpr]` bool QTime::isNull() const

Returns `true` if the time is null (i.e., the QTime object was constructed using the default constructor); otherwise returns false. A null time is also an invalid time.

See also isValid().

### bool QTime::isValid() const

Returns `true` if the time is valid; otherwise returns `false`. For example, the time 23:30:55.746 is valid, but 24:12:30 is invalid.

See also isNull().

### `[static]` bool QTime::isValid(int h, int m, int s, int ms = 0)

Returns `true` if the specified time is valid; otherwise returns false.

The time is valid if h is in the range 0 to 23, m and s are in the range 0 to 59, and ms is in the range 0 to 999.

Example:

     QTime::isValid(21, 10, 30); // returns true
     QTime::isValid(22, 5,  62); // returns false

This is an overloaded function.

### int QTime::minute() const

Returns the minute part (0 to 59) of the time.

Returns -1 if the time is invalid.

See also hour(), second(), and msec().

### int QTime::msec() const

Returns the millisecond part (0 to 999) of the time.

Returns -1 if the time is invalid.

See also hour(), minute(), and second().

### `[constexpr]` int QTime::msecsSinceStartOfDay() const

Returns the number of msecs since the start of the day, i.e. since 00:00:00.

See also fromMSecsSinceStartOfDay().

### int QTime::msecsTo(QTime t) const

Returns the number of milliseconds from this time to t. If t is earlier than this time, the number of milliseconds returned is negative.

Because QTime measures time within a day and there are 86400 seconds in a day, the result is always between -86400000 and 86400000 ms.

Returns 0 if either time is invalid.

See also secsTo(), addMSecs(), and QDateTime::msecsTo().

### int QTime::second() const

Returns the second part (0 to 59) of the time.

Returns -1 if the time is invalid.

See also hour(), minute(), and msec().

### int QTime::secsTo(QTime t) const

Returns the number of seconds from this time to t. If t is earlier than this time, the number of seconds returned is negative.

Because QTime measures time within a day and there are 86400 seconds in a day, the result is always between -86400 and 86400.

secsTo() does not take into account any milliseconds.

Returns 0 if either time is invalid.

See also addSecs() and QDateTime::secsTo().

### bool QTime::setHMS(int h, int m, int s, int ms = 0)

Sets the time to hour h, minute m, seconds s and milliseconds ms.

h must be in the range 0 to 23, m and s must be in the range 0 to 59, and ms must be in the range 0 to 999. Returns `true` if the set time is valid; otherwise returns `false`.

See also isValid().

## Related Non-Members

### `[constexpr noexcept]` bool operator!=(const QTime &lhs, const QTime &rhs)

Returns `true` if lhs is different from rhs; otherwise returns `false`.

### `[constexpr noexcept]` bool operator<(const QTime &lhs, const QTime &rhs)

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

### QDataStream &operator<<(QDataStream &out, QTime time)

Writes time to stream out.

See also Serializing Qt Data Types.

### `[constexpr noexcept]` bool operator<=(const QTime &lhs, const QTime &rhs)

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

### `[constexpr noexcept]` bool operator==(const QTime &lhs, const QTime &rhs)

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

### `[constexpr noexcept]` bool operator>(const QTime &lhs, const QTime &rhs)

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

### `[constexpr noexcept]` bool operator>=(const QTime &lhs, const QTime &rhs)

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

### QDataStream &operator>>(QDataStream &in, QTime &time)

Reads a time from stream in into the given time.

See also Serializing Qt Data Types.