[#BloombergLP-bdlt-Datetime]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlt.adoc[bdlt]::Datetime
:relfileprefix: ../../
:mrdocs:

This class implements a simply‐constrained value‐semantic type representing the composition of date and time values. Valid date values for the "date" part of a `Datetime` object are the same as those defined for `Date` objects; similarly, valid time values for the "time" part of a `Datetime` object are similar to those defined for `Time` objects (but with additional precision). Relational operators are disallowed on `Datetime` objects whose "time" part has the same value as that of a default constructed `Time` object.

== Synopsis

Declared in `<bdlt_datetime.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class Datetime;
----

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlt/Datetime/2constructor-0f.adoc[`Datetime`]         [.small]#[constructor]#
| Constructors
| xref:BloombergLP/bdlt/Datetime/operator_assign.adoc[`operator=`] 
| Assign to this object the value of the specified `rhs` object, and return a reference providing modifiable access to this object.
| xref:BloombergLP/bdlt/Datetime/addDays.adoc[`addDays`] 
| Add the specified number of `days` to the value of this object. Return a reference providing modifiable access to this object. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object. Note that this method has no effect on the "time" part of this object. Also note that `days` may be positive, 0, or negative.
| xref:BloombergLP/bdlt/Datetime/addDaysIfValid.adoc[`addDaysIfValid`] 
| Add the specified number of `days` to the value of this object, if the resulting value is in the valid range for a `Datetime` object. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that this method has no effect on the "time" part of this object. Also note that `days` may be positive, 0, or negative.
| xref:BloombergLP/bdlt/Datetime/addHours.adoc[`addHours`] 
| Add the specified number of `hours` to the value of this object, adjusting the "date" part of the object accordingly. Return a reference providing modifiable access to this object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object. Note that `hours` may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addHoursIfValid.adoc[`addHoursIfValid`] 
| Add the specified number of `hours` to the value of this object, adjusting the "date" part of the object accordingly, if the resulting value is in the valid range for a `Datetime` object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that `hours` may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addMicroseconds.adoc[`addMicroseconds`] 
| Add the specified number of `microseconds` to the value of this object, adjusting the "date" part of the object accordingly. Return a reference providing modifiable access to this object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object. Note that `microseconds` may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addMicrosecondsIfValid.adoc[`addMicrosecondsIfValid`] 
| Add the specified number of `microseconds` to the value of this object, adjusting the "date" part of the object accordingly, if the resulting value is in the valid range for a `Datetime` object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that `microseconds` may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addMilliseconds.adoc[`addMilliseconds`] 
| Add the specified number of `milliseconds` to the value of this object, adjusting the "date" part of the object accordingly. Return a reference providing modifiable access to this object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object. Note that `milliseconds` may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addMillisecondsIfValid.adoc[`addMillisecondsIfValid`] 
| Add the specified number of `milliseconds` to the value of this object, adjusting the "date" part of the object accordingly, if the resulting value is in the valid range for a `Datetime` object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that `milliseconds` may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addMinutes.adoc[`addMinutes`] 
| Add the specified number of `minutes` to the value of this object, adjusting the "date" part of the object accordingly. Return a reference providing modifiable access to this object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object. Note that `minutes` may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addMinutesIfValid.adoc[`addMinutesIfValid`] 
| Add the specified number of `minutes` to the value of this object, adjusting the "date" part of the object accordingly, if the resulting value is in the valid range for a `Datetime` object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that `minutes` may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addSeconds.adoc[`addSeconds`] 
| Add the specified number of `seconds` to the value of this object, adjusting the "date" part of the object accordingly. Return a reference providing modifiable access to this object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object. Note that `seconds` may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addSecondsIfValid.adoc[`addSecondsIfValid`] 
| Add the specified number of `seconds` to the value of this object, adjusting the "date" part of the object accordingly, if the resulting value is in the valid range for a `Datetime` object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that `seconds` may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addTime.adoc[`addTime`] 
| Add the specified number of `hours`, and the optionally specified number of `minutes`, `seconds`, `milliseconds`, and `microseconds` to the value of this object, adjusting the "date" part of this object accordingly. Unspecified trailing optional parameters default to 0. Return a reference providing modifiable access to this object. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object. Note that each argument independently may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/addTimeIfValid.adoc[`addTimeIfValid`] 
| Add the specified number of `hours`, and the optionally specified number of `minutes`, `seconds`, `milliseconds`, and `microseconds` to the value of this object, adjusting the "date" part of this object accordingly, if the resulting value is in the valid range for a `Datetime` object. Unspecified trailing optional parameters default to 0. If `24 == hour()` on entry, set the `hour` attribute to 0 before performing the addition. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that each argument independently may be positive, negative, or 0.
| xref:BloombergLP/bdlt/Datetime/bdexStreamIn.adoc[`bdexStreamIn`] 
| Assign to this object the value read from the specified input `stream` using the specified `version` format, and return a reference to `stream`. If `stream` is initially invalid, this operation has no effect. If `version` is not supported, this object is unaltered and `stream` is invalidated, but otherwise unmodified. If `version` is supported but `stream` becomes invalid during this operation, this object has an undefined, but valid, state. Note that no version is read from `stream`. See the `bslx` package‐level documentation for more information on BDEX streaming of value‐semantic types and containers.
| xref:BloombergLP/bdlt/Datetime/bdexStreamOut.adoc[`bdexStreamOut`] 
| Write the value of this object, using the specified `version` format, to the specified output `stream`, and return a reference to `stream`. If `stream` is initially invalid, this operation has no effect. If `version` is not supported, `stream` is invalidated, but otherwise unmodified. Note that `version` is not written to `stream`. See the `bslx` package‐level documentation for more information on BDEX streaming of value‐semantic types and containers.
| xref:BloombergLP/bdlt/Datetime/date.adoc[`date`] 
| Return the value of the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/day.adoc[`day`] 
| Return the value of the `day` (of the month) attribute of this object.
| xref:BloombergLP/bdlt/Datetime/dayOfWeek.adoc[`dayOfWeek`] 
| Return the value of the `dayOfWeek` attribute associated with the `day` (of the month) attribute of this object.
| xref:BloombergLP/bdlt/Datetime/dayOfYear.adoc[`dayOfYear`] 
| Return the value of the `dayOfYear` attribute of this object.
| xref:BloombergLP/bdlt/Datetime/getTime.adoc[`getTime`] 
| Load, into the specified `hour`, and the optionally specified `minute`, `second`, `millisecond`, and `microsecond` the respective `hour`, `minute`, `second`, `millisecond`, and `microsecond` attribute values from this time object. Unspecified arguments default to 0. Supplying 0 for an address argument suppresses the loading of the value for the corresponding attribute, but has no effect on the loading of other attribute values.
| xref:BloombergLP/bdlt/Datetime/hour.adoc[`hour`] 
| Return the value of the `hour` attribute of this object.
| xref:BloombergLP/bdlt/Datetime/microsecond.adoc[`microsecond`] 
| Return the value of the `microsecond` attribute of this object.
| xref:BloombergLP/bdlt/Datetime/millisecond.adoc[`millisecond`] 
| Return the value of the `millisecond` attribute of this object.
| xref:BloombergLP/bdlt/Datetime/minute.adoc[`minute`] 
| Return the value of the `minute` attribute of this object.
| xref:BloombergLP/bdlt/Datetime/month.adoc[`month`] 
| Return the value of the `month` attribute of this object.
| xref:BloombergLP/bdlt/Datetime/operator_plus_eq-0a.adoc[`operator+=`] 
| Addition assignment operators
| xref:BloombergLP/bdlt/Datetime/operator_minus_eq-0e.adoc[`operator‐=`] 
| Subtraction assignment operators
| xref:BloombergLP/bdlt/Datetime/print.adoc[`print`] 
| Write the value of this object to the specified output `stream` in a human‐readable format, and return a reference to `stream`. Optionally specify an initial indentation `level`, whose absolute value is incremented recursively for nested objects. If `level` is specified, optionally specify `spacesPerLevel`, whose absolute value indicates the number of spaces per indentation level for this and all of its nested objects. If `level` is negative, suppress indentation of the first line. If `spacesPerLevel` is negative, format the entire output on one line, suppressing all but the initial indentation (as governed by `level`). If `stream` is not valid on entry, this operation has no effect. Note that this human‐readable format is not fully specified, and can change without notice.
| xref:BloombergLP/bdlt/Datetime/printToBuffer.adoc[`printToBuffer`] 
| Efficiently write to the specified `result` buffer no more than the specified `numBytes` of a representation of the value of this object. Optionally specify `fractionalSecondPrecision` digits to indicate how many fractional second digits to output. If `fractionalSecondPrecision` is not specified then 6 fractional second digits will be output (3 digits for milliseconds and 3 digits for microseconds). Return the number of characters (not including the null character) that would have been written if the limit due to `numBytes` were not imposed. `result` is null‐terminated unless `numBytes` is 0. The behavior is undefined unless `0 <= numBytes`, `0 <= fractionalSecondPrecision <= 6`, and `result` refers to at least `numBytes` contiguous bytes. Note that the return value is greater than or equal to `numBytes` if the output representation was truncated to avoid `result` overrun.
| xref:BloombergLP/bdlt/Datetime/second.adoc[`second`] 
| Return the value of the `second` attribute of this object.
| xref:BloombergLP/bdlt/Datetime/setDate.adoc[`setDate`] 
| Set the "date" part of this object to have the value of the specified `date`. Note that this method has no effect on the "time" part of this object.
| xref:BloombergLP/bdlt/Datetime/setDatetime-0f.adoc[`setDatetime`] 
| `setDatetime` overloads
| xref:BloombergLP/bdlt/Datetime/setDatetimeIfValid-03.adoc[`setDatetimeIfValid`] 
| `setDatetimeIfValid` overloads
| xref:BloombergLP/bdlt/Datetime/setHour.adoc[`setHour`] 
| Set the "hour" attribute of this object to the specified `hour` value. If `24 == hour`, set the `minute`, `second`, `millisecond`, and `microsecond` attributes to 0. The behavior is undefined unless `0 <= hour <= 24`. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setHourIfValid.adoc[`setHourIfValid`] 
| Set the "hour" attribute of this object to the specified `hour` value if `0 <= hour <= 24`. If `24 == hour`, set the `minute`, `second`, `millisecond`, and `microsecond` attributes to 0. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setMicrosecond.adoc[`setMicrosecond`] 
| Set the "microsecond" attribute of this object to the specified `microsecond` value. If `24 == hour()`, set the `hour` attribute to 0. The behavior is undefined unless `0 <= microsecond <= 999`. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setMicrosecondIfValid.adoc[`setMicrosecondIfValid`] 
| Set the "microsecond" attribute of this object to the specified `microsecond` value if `0 <= microsecond <= 999`. If `24 == hour()`, set the `hour` attribute to 0. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setMillisecond.adoc[`setMillisecond`] 
| Set the "millisecond" attribute of this object to the specified `millisecond` value. If `24 == hour()`, set the `hour` attribute to 0. The behavior is undefined unless `0 <= millisecond <= 999`. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setMillisecondIfValid.adoc[`setMillisecondIfValid`] 
| Set the "millisecond" attribute of this object to the specified `millisecond` value if `0 <= millisecond <= 999`. If `24 == hour()`, set the `hour` attribute to 0. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setMinute.adoc[`setMinute`] 
| Set the "minute" attribute of this object to the specified `minute` value. If `24 == hour()`, set the `hour` attribute to 0. The behavior is undefined unless `0 <= minute <= 59`. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setMinuteIfValid.adoc[`setMinuteIfValid`] 
| Set the "minute" attribute of this object to the specified `minute` value if `0 <= minute <= 59`. If `24 == hour()`, set the `hour` attribute to 0. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setSecond.adoc[`setSecond`] 
| Set the "second" attribute of this object to the specified `second` value. If `24 == hour()`, set the `hour` attribute to 0. The behavior is undefined unless `0 <= second <= 59`. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setSecondIfValid.adoc[`setSecondIfValid`] 
| Set the "second" attribute of this object to the specified `second` value if `0 <= second <= 59`. If `24 == hour()`, set the `hour` attribute to 0. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setTime-09.adoc[`setTime`] 
| `setTime` overloads
| xref:BloombergLP/bdlt/Datetime/setTimeIfValid.adoc[`setTimeIfValid`] 
| Set the "time" part of this object to have the value represented by the specified `hour` attribute value and the optionally specified `minute`, `second`, `millisecond`, and `microsecond` attribute values if they comprise a valid "time" portion of a `DateTime` value. Unspecified trailing optional parameters default to 0. Return 0 on success, and a non‐zero value (with no effect) otherwise. Note that this method has no effect on the "date" part of this object.
| xref:BloombergLP/bdlt/Datetime/setYearDay.adoc[`setYearDay`] 
| Set the "date" part of this object to have the value represented by the specified `year` and `dayOfYear` attribute values. The behavior is undefined unless `year` and `dayOfYear` represent a valid `Date` value (i.e., `true == Date::isValidYearDay(year, dayOfYear)`). Note that this method has no effect on the "time" part of this object.
| xref:BloombergLP/bdlt/Datetime/setYearDayIfValid.adoc[`setYearDayIfValid`] 
| Set this object to have the value represented by the specified `year` and `dayOfYear` if they comprise a valid `Date` value (see `Date::isValidYearDay`). Return 0 on success, and a non‐zero value (with no effect) otherwise.
| xref:BloombergLP/bdlt/Datetime/setYearMonthDay.adoc[`setYearMonthDay`] 
| Set the "date" part of this object to have the value represented by the specified `year`, `month`, and `day` attribute values. The behavior is undefined unless `year`, `month`, and `day` represent a valid `Date` value (i.e., `true == Date::isValidYearMonthDay(year, month, day)`). Note that this method has no effect on the "time" part of this object.
| xref:BloombergLP/bdlt/Datetime/setYearMonthDayIfValid.adoc[`setYearMonthDayIfValid`] 
| Set this object to have the value represented by the specified `year`, `month`, and `day` if they comprise a valid `Date` value (see `Date::isValidYearMonthDay`). Return 0 on success, and a non‐zero value (with no effect) otherwise.
| xref:BloombergLP/bdlt/Datetime/streamOut.adoc[`streamOut`] 
| Format this datetime to the specified output `stream` and return a reference to the modifiable `stream`.
| xref:BloombergLP/bdlt/Datetime/time.adoc[`time`] 
| Return the value of the "time" part of this object.
| xref:BloombergLP/bdlt/Datetime/validateAndSetDatetime.adoc[`validateAndSetDatetime`] 
| Set the "date" part of this object's value to the specified `year`, `month`, and `day`, and the "time" part to the optionally specified `hour`, `minute`, `second`, and `millisecond`, if they represent a valid `Datetime` value, with trailing fields that are not specified set to 0. Return 0 on success, and a non‐zero value (with no effect) otherwise.
| xref:BloombergLP/bdlt/Datetime/year.adoc[`year`] 
| Return the value of the `year` attribute of this object.
|===


== Static Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlt/Datetime/isValid.adoc[`isValid`] 
| Return `true` if the specified `year`, `month`, and `day` attribute values, and the optionally specified `hour`, `minute`, `second`, `millisecond`, and `microsecond` attribute values, represent a valid `Datetime` value, and `false` otherwise. Unspecified trailing optional parameters default to 0. `year`, `month`, `day`, `hour`, `minute`, `second`, `millisecond`, and `microsecond` attribute values represent a valid `Datetime` value if `true == Date::isValidYearMonthDay(year, month, day)`, `0 <= hour < 24`, `0 <= minute < 60`, `0 <= second < 60`, `0 <= millisecond < 1000`, and `0 <= microsecond < 1000`. Additionally, a valid `year`, `month`, `day` with the time portion equal to 24:00:00.000000 also represents a valid `Datetime` value.
| xref:BloombergLP/bdlt/Datetime/maxSupportedBdexVersion-04.adoc[`maxSupportedBdexVersion`] 
| `maxSupportedBdexVersion` overloads
| xref:BloombergLP/bdlt/Datetime/maxSupportedVersion.adoc[`maxSupportedVersion`] 
| Return the most current BDEX streaming version number supported by this class.
|===


== Friends

[cols="1,4"]
|===
| Name| Description
| `xref:BloombergLP/bdlt/hashAppend-01.adoc[BloombergLP::bdlt::hashAppend]`
| Pass the specified `object` to the specified `hashAlg`. This function integrates with the `bslh` modular hashing system and effectively provides a `bsl::hash` specialization for `Datetime`.
| `xref:BloombergLP/bdlt/operator_ge-03.adoc[BloombergLP::bdlt::operator>=]`
| Return `true` if the value of the specified `lhs` object is greater than or equal to the value of the specified `rhs` object, and `false` otherwise. The behavior is undefined unless `24 != lhs.hour() && 24 != rhs.hour()`.
| `xref:BloombergLP/bdlt/operator_gt-02.adoc[BloombergLP::bdlt::operator>]`
| Return `true` if the value of the specified `lhs` object is greater than the value of the specified `rhs` object, and `false` otherwise. A `Datetime` object `a` is greater than a `Datetime` object `b` if `a.date() > b.date()`, or if `a.date() == b.date()` and the time portion of `a` is greater than the time portion of `b`. The behavior is undefined unless `24 != lhs.hour() && 24 != rhs.hour()`.
| `xref:BloombergLP/bdlt/operator_le-01.adoc[BloombergLP::bdlt::operator<=]`
| Return `true` if the value of the specified `lhs` object is less than or equal to the value of the specified `rhs` object, and `false` otherwise. The behavior is undefined unless `24 != lhs.hour() && 24 != rhs.hour()`.
| `xref:BloombergLP/bdlt/operator_lt-0d.adoc[BloombergLP::bdlt::operator<]`
| Return `true` if the value of the specified `lhs` object is less than the value of the specified `rhs` object, and `false` otherwise. A `Datetime` object `a` is less than a `Datetime` object `b` if `a.date() < b.date()`, or if `a.date() == b.date()` and the time portion of `a` is less than the time portion of `b`. The behavior is undefined unless `24 != lhs.hour() && 24 != rhs.hour()`.
| `xref:BloombergLP/bdlt/operator_not_eq-02.adoc[BloombergLP::bdlt::operator!=]`
| Return `true` if the specified `lhs` and `rhs` `Datetime` objects do not have the same value, and `false` otherwise. Two `Datetime` objects do not have the same value if they do not have the same values for either of their "date" or "time" parts, respectively.
| `xref:BloombergLP/bdlt/operator_eq-022.adoc[BloombergLP::bdlt::operator==]`
| Return `true` if the specified `lhs` and `rhs` objects have the same value, and `false` otherwise. Two `Datetime` objects have the same value if they have the same values for their "date" and "time" parts, respectively.
| `xref:BloombergLP/bdlt/operator_minus-0c.adoc[BloombergLP::bdlt::operator‐]`
| Return a `DatetimeInterval` object having a value that is the difference between the specified `lhs` (`Datetime`) and the specified `rhs` (`Datetime`). If the `hour` attribute of either operand is 24, the result is the same as if that `hour` attribute is 0. The behavior is undefined unless the resulting value is in the valid range for a `DatetimeInterval` object.
|===

== Non-Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlt/operator_plus-069.adoc[`operator+`]
| Return a `Datetime` object having a value that is the sum of the specified `lhs` (`bsls::TimeInterval`) and the specified `rhs` (`Datetime`). If `24 == rhs.hour()`, the result is the same as if the `hour` attribute of `rhs` is 0. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object.
| xref:BloombergLP/bdlt/operator_plus-07.adoc[`operator+`]
| Return a `Datetime` object having a value that is the sum of the specified `lhs` (`Datetime`) and the specified `rhs` (`bsls::TimeInterval`). If `24 == lhs.hour()`, the result is the same as if the `hour` attribute of `lhs` is 0. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object.
| xref:BloombergLP/bdlt/operator_plus-087.adoc[`operator+`]
| Return a `Datetime` object having a value that is the sum of the specified `lhs` (`DatetimeInterval`) and the specified `rhs` (`Datetime`). If `24 == rhs.hour()`, the result is the same as if the `hour` attribute of `rhs` is 0. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object.
| xref:BloombergLP/bdlt/operator_plus-09.adoc[`operator+`]
| Return a `Datetime` object having a value that is the sum of the specified `lhs` (`Datetime`) and the specified `rhs` (`DatetimeInterval`). If `24 == lhs.hour()`, the result is the same as if the `hour` attribute of `lhs` is 0. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object.
| xref:BloombergLP/bdlt/operator_minus-06.adoc[`operator‐`]
| Return a `Datetime` object having a value that is the difference between the specified `lhs` (`Datetime`) and the specified `rhs` (`bsls::TimeInterval`). If `24 == lhs.hour()`, the result is the same as if the `hour` attribute of `lhs` is 0. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object.
| xref:BloombergLP/bdlt/operator_minus-07.adoc[`operator‐`]
| Return a `Datetime` object having a value that is the difference between the specified `lhs` (`Datetime`) and the specified `rhs` (`DatetimeInterval`). If `24 == lhs.hour()`, the result is the same as if the `hour` attribute of `lhs` is 0. The behavior is undefined unless the resulting value is in the valid range for a `Datetime` object.
| xref:BloombergLP/bdlt/operator_lt-034.adoc[`operator<`]
| Return `true` if the specified `lhs` has a value less than the specified `rhs`, and `false` otherwise. Datetime `lhs` has a value less than timetable transition `rhs` if `lhs < rhs.datetime()`. The behavior is undefined unless `24 > lhs.hour()`.
|===


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