Boost C++ Libraries

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posix_time::time_duration

Introduction

The class boost::posix_time::time_duration the base type responsible for representing a length of time. A duration can be either positive or negative. The general time_duration class provides a constructor that takes a count of the number of hours, minutes, seconds, and fractional seconds count as shown in the code fragment below. The resolution of the time_duration is configureable at compile time. See Build-Compiler Information for more information.


  using namespace boost::posix_time;

  time_duration td(1,2,3,4); //01:02:03.000000004 when resolution is nano seconds
  time_duration td(1,2,3,4); //01:02:03.000004 when resolution is micro seconds

Several small helper classes that derive from a base time_duration, as shown below, to adjust for different resolutions. These classes can shorten code and make the intent clearer.


  using namespace boost::posix_time;

  time_duration td = hours(1) + seconds(10); //01:00:01
  td = hours(1) + nanosec(5); //01:00:00.000000005

Note that the existence of the higher resolution classes (eg: nanosec) depends on the installation of the library. See Build-Compiler Information for more information.

Header

Construction

Syntax	Description	Example
time_duration(hours,minutes,seconds,fractional_seconds)	Construct a duration from the counts	time_duration td(1,2,3,9); //1 hr 2 min 3 sec 9 nanoseconds
time_duration(special_values)	Construct a time duration with a special value such as not_a_date_time, pos_infin, or neg_infin.	time_duration td(not_a_date_time); //invalid value

Construction By Count

Construction From String

Syntax	Description	Example
time_duration duration_from_string(const std::string&)	From delimited string.	std::string ts("23:59:59.000"); time_duraton td(duration_from_string(ts))

Accessors

Syntax	Description	Example
long hours() const	Get the number of normalized hours.	time_duration td(1,2,3); td.hours() --> 1
long minutes() const	Get the number of minutes normalized (0..59).	time_duration td(1,2,3); td.minutes() --> 2
long seconds() const	Get the normalized number of second (0..59).	time_duration td(1,2,3); td.seconds() --> 3
bool is_special() const	Returns true if the value of the duration is a special value, otherwise false.	time_duration td(neg_infin); td.is_special() --> true
bool is_neg_infinity() const	Returns true if the value of the duration is negative infinity, otherwise false.	time_duration td(neg_inifin); td.is_neg_infinity() --> true
bool is_pos_infinity() const	Returns true if the value of the duration is positive infinity, otherwise false.	hours h(5); h.is_pos_infinity() --> false
long total_seconds() const	Get the total number of seconds truncating any fractional seconds.	time_duration td(1,2,3,10); td.total_seconds() --> (13600) + (260) + 3 == 3723
long total_microseconds() const	Return the total number of microseconds in the duration truncating any fractional lower resolution (eg: nano second counts).	seconds(1).total_microseconds() == 1000000
long total_milliseconds() const	Return the total number of milliseconds in the duration truncating any fractional lower resolution (eg: micro or nano second counts).	seconds(1).total_milliseconds() == 1000
long total_nanoseconds() const	Return the total number of nanoseconds in the duration.	seconds(1).total_nanoseconds() == 1000000000
long fractional_seconds() const	Get the fractional seconds count. Note that the results of this method vary based on the resolution of template instantiation for the time duration (Normally either a nano-second or millisecond count).	time_duration td(1,2,3, 1000); td.fractional_seconds() --> 1000
bool is_negative() const	True if duration is negative.	time_duration td(-1,0,0); td.is_negative() --> true
boost::int64_t ticks()	Return the raw count of the duration type.	time_duration td(0,0,0, 1000); td.ticks() --> 1000
static boost::int64_t ticks_per_second()	Return the number of ticks held internally to represent a second, which is driven by the resolution settings. For nano second resolution the value 1000000000.	time_duration::ticks_per_second() == 1000000000 //nano second resolution
static time_duration unit()	Return smallest possible unit of duration type (1 nanosecond).	time_duration::unit() --> time_duration(0,0,0,1)

Conversion To String

Syntax	Description	Example
std::string to_simple_string(time_duration)	To HH:MM:SS.fffffffff were fff is fractional seconds that are only included if non-zero.	10:00:01.123456789
std::string to_iso_string(time_duration)	Convert to form HHMMSS,fffffffff.	100001,123456789

Operators

Syntax	Description	Example
operator==, operator!=, operator>, operator< operator>=, operator<=	A full complement of comparison operators	td1 == td2, etc
time_duration operator+(time_duration) const	Add durations.	time_duration td1(hours(1)+minutes(2)); time_duration td2(seconds(10)); time_duration td3 = td1 + td2;
time_duration operator-(time_duration) const	Subtract durations.	time_duration td1(hours(1)+nanosec(2)); time_duration td2 = td1 - minutes(1);
time_duration operator-() const	Invert sign.	time_duration td1(hours(1)); -td1; //equal -1 hour
time_duration operator/(int) const	Divide the length of a duration by an integer value. Discards any remainder.	hours(3)/2 == time_duration(1,30,0); nanosec(3)/2 == nanosec(1)
time_duration operator*(int) const	Multiply the length of a duration by an integer value.	hours(3)*2 == hours(6);

Syntax	Description	Example
hours(long)	Number of hours	time_duration td = hours(3);
minutes(long)	Number of minutes	time_duration td = minutes(3);
seconds(long)	Number of seconds	time_duration td = seconds(3);
milliseconds(long)	Number of milliseconds.	time_duration td = milliseconds(3);
microseconds(long)	Number of microseconds.	time_duration td = microseconds(3);
nanoseconds(long)	Number of nanoseconds.	time_duration td = nanoseconds(3);