QTime Class Reference

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

#include <qdatetime.h>

Public Member Functions
	QTime ()
	QTime (int h, int m, int s=0, int ms=0)
bool	isNull () const
bool	isValid () const
int	hour () const
int	minute () const
int	second () const
int	msec () const
QString	toString () const
bool	setHMS (int h, int m, int s, int ms=0)
QTime	addSecs (int secs) const
int	secsTo (const QTime &) const
QTime	addMSecs (int ms) const
int	msecsTo (const QTime &) const
bool	operator== (const QTime &d) const
bool	operator!= (const QTime &d) const
bool	operator< (const QTime &d) const
bool	operator<= (const QTime &d) const
bool	operator> (const QTime &d) const
bool	operator>= (const QTime &d) const
void	start ()
int	restart ()
int	elapsed ()

Static Public Member Functions
static QTime	currentTime ()
static bool	isValid (int h, int m, int s, int ms=0)

Static Private Member Functions
static bool	currentTime (QTime *)

Private Attributes
uint	ds

Friends
class	QDateTime
Q_EXPORT QDataStream &	operator<< (QDataStream &, const QTime &)
Q_EXPORT QDataStream &	operator>> (QDataStream &, QTime &)

Detailed Description

The QTime class provides clock time functions.

A QTime object contains a clock time, i.e. a number of hours, minutes, seconds and milliseconds since midnight. It can read the current time from the system clock, and measure a span of elapsed time. It provides functions for comparing times and for manipulating a time by adding a number of (milli)seconds.

QTime operates with 24-hour clock format; it has no concept of AM/PM. It operates with local time; it does not know anything about time zones or daylight savings time.

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 makes a QTime object which contains the system's clock time. Note that the accuracy depends on the accuracy of the underlying operating system; not all systems provide 1-millisecond accuracy.

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.

QTime provides a full set of operators to compare two QTime objects. A time is considered smaller than another if it is earlier than the other.

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

QTime can be used to measure a span of elapsed time using the start(), restart(), and elapsed() functions.

See also

QDate, QDateTime

Definition at line 108 of file qdatetime.h.

Constructor & Destructor Documentation

QTime::QTime ( )

inline

Constructs the time 0 hours, minutes, seconds and milliseconds, i.e. 00:00:00.000 (midnight). This is a valid time.

See also

isValid()

Definition at line 111 of file qdatetime.h.

{ ds=0; }                               // set null time

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

See also

isValid()

Definition at line 618 of file qdatetime.cpp.

{
    setHMS( h, m, s, ms );
}

Member Function Documentation

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.

See also

addSecs(), msecsTo()

Definition at line 769 of file qdatetime.cpp.

{
    QTime t;
    if ( ms < 0 ) {
        // % not well-defined for -ve, but / is.
        int negdays = (MSECS_PER_DAY-ms) / MSECS_PER_DAY;
        t.ds = ((int)ds + ms + negdays*MSECS_PER_DAY)
                % MSECS_PER_DAY;
    } else {
        t.ds = ((int)ds + ms) % MSECS_PER_DAY;
    }
    return t;
}

QTime QTime::addSecs

(

int

nsecs

)

const

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

Note that the time will wrap if it passes midnight.

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(), QDateTime::addSecs()

Definition at line 739 of file qdatetime.cpp.

{
    return addMSecs(nsecs*1000);
}

QTime QTime::currentTime ( )

static

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.

Definition at line 848 of file qdatetime.cpp.

{
    QTime ct;
    currentTime( &ct );
    return ct;
}

bool QTime::currentTime ( QTime *  ct )

staticprivate

Definition at line 863 of file qdatetime.cpp.

{
    if ( !ct ) {
#if defined(CHECK_NULL)
        qWarning( "QTime::currentTime(QTime *): Null pointer not allowed" );
#endif
        return FALSE;
    }

#if defined(_OS_WIN32_)

    SYSTEMTIME t;
    GetLocalTime( &t );
    ct->ds = MSECS_PER_HOUR*t.wHour + MSECS_PER_MIN*t.wMinute +
             1000*t.wSecond + t.wMilliseconds;
    return (t.wHour == 0 && t.wMinute == 0);

#elif defined(_OS_OS2_)

    DATETIME t;
    DosGetDateTime( &t );
    ct->ds = MSECS_PER_HOUR*t.hours + MSECS_PER_MIN*t.minutes +
             1000*t.seconds + 10*t.hundredths;
    return (t.hours == 0 && t.minutes == 0);

#elif defined(_OS_MSDOS_)

    _dostime_t t;
    _dos_gettime( &t );
    ct->ds = MSECS_PER_HOUR*t.hour + MSECS_PER_MIN*t.minute +
             t.second*1000 + t.hsecond*10;
    return (t.hour== 0 && t.minute == 0);

#elif defined(_OS_UNIX_) || defined(_OS_MAC_)

    struct timeval tv;
    gettimeofday( &tv, 0 );
    time_t ltime = tv.tv_sec;
    tm *t = localtime( &ltime );
    ct->ds = (uint)( MSECS_PER_HOUR*t->tm_hour + MSECS_PER_MIN*t->tm_min +
                     1000*t->tm_sec + tv.tv_usec/1000 );
    return (t->tm_hour== 0 && t->tm_min == 0);

#else

    time_t ltime;                       // no millisecond resolution!!
    ::time( &ltime );
    tm *t = localtime( &ltime );
    ct->ds = MSECS_PER_HOUR*t->tm_hour + MSECS_PER_MIN*t->tm_min +
             1000*t->tm_sec;
    return (t->tm_hour== 0 && t->tm_min == 0);
#endif
}

int QTime::elapsed

(

)

Returns the number of milliseconds that have elapsed since the last time start() or restart() was called.

Note that the counter wraps to zero 24 hours after the last call to start() or restart.

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

Warning

If the system's clock setting has been changed since the last time start() or restart() was called, the result is undefined. This can happen e.g. when daylight saving is turned on or off.

See also

start(), restart()

Definition at line 1000 of file qdatetime.cpp.

{
    int n = msecsTo( currentTime() );
    if ( n < 0 )                                // passed midnight
        n += 86400*1000;
    return n;
}

int QTime::hour

(

)

const

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

Definition at line 648 of file qdatetime.cpp.

{
    return ds / MSECS_PER_HOUR;
}

bool QTime::isNull ( ) const

inline

Returns TRUE if the time is equal to 00:00:00.000. A null time is valid.

See also

isValid()

Definition at line 114 of file qdatetime.h.

{ return ds == 0; }

bool QTime::isValid

(

)

const

Returns TRUE if the time is valid, or FALSE if the time is invalid. The time 23:30:55.746 is valid, while 24:12:30 is invalid.

See also

isNull()

Definition at line 638 of file qdatetime.cpp.

{
    return ds < MSECS_PER_DAY;
}

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

static

Returns TRUE if the specified time is valid, otherwise FALSE.

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

Example:

QTime::isValid(21, 10, 30);           // returns TRUE
QTime::isValid(22, 5,  62);           // returns FALSE

Definition at line 930 of file qdatetime.cpp.

{
    return (uint)h < 24 && (uint)m < 60 && (uint)s < 60 && (uint)ms < 1000;
}

int QTime::minute

(

)

const

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

Definition at line 657 of file qdatetime.cpp.

{
    return (ds % MSECS_PER_HOUR)/MSECS_PER_MIN;
}

int QTime::msec

(

)

const

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

Definition at line 675 of file qdatetime.cpp.

{
    return ds % 1000;
}

int QTime::msecsTo

(

const QTime &

t

)

const

Returns the number of milliseconds from this time to t (which is negative if t is earlier than this time).

Since QTime measures time within a day and there are 86400000 milliseconds in a day, the result is between -86400000 and 86400000.

See also

secsTo()

Definition at line 793 of file qdatetime.cpp.

{
    return (int)t.ds - (int)ds;
}

bool QTime::operator!= ( const QTime &  t ) const

inline

Returns TRUE if this time is different from t, or FALSE if they are equal.

Definition at line 132 of file qdatetime.h.

{ return ds != d.ds; }

bool QTime::operator< ( const QTime &  t ) const

inline

Returns TRUE if this time is earlier than t, otherwise FALSE.

Definition at line 133 of file qdatetime.h.

{ return ds < d.ds; }

bool QTime::operator<= ( const QTime &  t ) const

inline

Returns TRUE if this time is earlier than or equal to t, otherwise FALSE.

Definition at line 134 of file qdatetime.h.

{ return ds <= d.ds; }

bool QTime::operator== ( const QTime &  t ) const

inline

Returns TRUE if this time is equal to t, or FALSE if they are different.

Definition at line 131 of file qdatetime.h.

{ return ds == d.ds; }

bool QTime::operator> ( const QTime &  t ) const

inline

Returns TRUE if this time is later than t, otherwise FALSE.

Definition at line 135 of file qdatetime.h.

{ return ds > d.ds; }

bool QTime::operator>= ( const QTime &  t ) const

inline

Returns TRUE if this time is later than or equal to t, otherwise FALSE.

Definition at line 136 of file qdatetime.h.

{ return ds >= d.ds; }

int QTime::restart

(

)

Sets this time to the current time, and returns the number of milliseconds that have elapsed since the last time start() or restart() was called.

This function is guaranteed to be atomic, and is thus very handy for repeated measurements: call start() to start the first measurement, then restart() for each later measurement.

Note that the counter wraps to zero 24 hours after the last call to start() or restart().

Warning

If the system's clock setting has been changed since the last time start() or restart() was called, the result is undefined. This can happen e.g. when daylight saving is turned on or off.

See also

start(), elapsed(), currentTime()

Definition at line 973 of file qdatetime.cpp.

{
    QTime t = currentTime();
    int n = msecsTo( t );
    if ( n < 0 )                                // passed midnight
        n += 86400*1000;
    *this = t;
    return n;
}

int QTime::second

(

)

const

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

Definition at line 666 of file qdatetime.cpp.

{
    return (ds / 1000)%SECS_PER_MIN;
}

int QTime::secsTo

(

const QTime &

t

)

const

Returns the number of seconds from this time to t (which is negative if t is earlier than this time).

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

See also

addSecs() QDateTime::secsTo()

Definition at line 754 of file qdatetime.cpp.

{
    return ((int)t.ds - (int)ds)/1000;
}

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 0-23, m and s must be in the range 0-59, and ms must be in the range 0-999. Returns TRUE if the set time is valid, otherwise FALSE.

See also

isValid()

Definition at line 706 of file qdatetime.cpp.

{
    if ( !isValid(h,m,s,ms) ) {
#if defined(CHECK_RANGE)
        qWarning( "QTime::setHMS Invalid time %02d:%02d:%02d.%03d", h, m, s,
                 ms );
#endif
        ds = MSECS_PER_DAY;             // make this invalid
        return FALSE;
    }
    ds = (h*SECS_PER_HOUR + m*SECS_PER_MIN + s)*1000 + ms;
    return TRUE;
}

void QTime::start

(

)

Sets this time to the current time. This is practical for timing:

QTime t;
t.start();                            // start clock
... // some lengthy task
qDebug( "%d\n", t.elapsed() );        // prints # msecs elapsed

See also

restart(), elapsed(), currentTime()

Definition at line 949 of file qdatetime.cpp.

{
    *this = currentTime();
}

QString QTime::toString

(

)

const

Returns the time of this object in a textual format. Milliseconds are not included. The string format is HH:MM:SS, e.g. 1 second before midnight would be "23:59:59".

Definition at line 687 of file qdatetime.cpp.

{
    QString buf;
    buf.sprintf( "%.2d:%.2d:%.2d", hour(), minute(), second() );
    return buf;
}

Friends And Related Function Documentation

QDataStream & operator<< ( QDataStream &  s, const QTime &  t  )

friend

Writes a time to the stream.

See also

Format of the QDataStream operators

Definition at line 1390 of file qdatetime.cpp.

{
    return s << (Q_UINT32)(t.ds);
}

QDataStream & operator>> ( QDataStream &  s, QTime &  t  )

friend

Reads a time from the stream.

See also

Format of the QDataStream operators

Definition at line 1402 of file qdatetime.cpp.

{
    Q_UINT32 ds;
    s >> ds;
    t.ds = ds;
    return s;
}

friend class QDateTime

friend

Definition at line 149 of file qdatetime.h.

Member Data Documentation

uint QTime::ds

private

Definition at line 148 of file qdatetime.h.

---

The documentation for this class was generated from the following files:

• doxygen-1.8.11/qtools/qdatetime.h
• doxygen-1.8.11/qtools/qdatetime.cpp