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

This `struct` provides a namespace for a suite of pure functions that perform low‐level operations on date values in a variety of formats. Note that all of these functions, whether or not implemented in terms of a static cache, are stateless, and, as such, are inherently thread‐safe.

== Synopsis

Declared in `<bdlt_posixdateimputil.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
struct PosixDateImpUtil;
----

== Static Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlt/PosixDateImpUtil/isLeapYear.adoc[`isLeapYear`] 
| Return `true` if the specified `year` is a leap year, and `false` otherwise. The behavior is undefined unless `1 <= year <= 9999`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/isValidSerial.adoc[`isValidSerial`] 
| Return `true` if the specified `serialDay` represents a valid date value, and `false` otherwise. Note that valid date values are (as fully defined in the component‐level documentation) in the range `[ 1 .. 3652061 ]`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/isValidYearDay.adoc[`isValidYearDay`] 
| Return `true` if the specified `year` and `dayOfYear` represents a valid date value, and `false` otherwise. Note that valid date values are (as fully defined in the component‐level documentation) in the range `[ 0001/01 .. 9999/365 ]` (except that `[ 1752/356 .. 1752/366 ]` are not valid for historical reasons).
| xref:BloombergLP/bdlt/PosixDateImpUtil/isValidYearMonthDay.adoc[`isValidYearMonthDay`] 
| Return `true` if the specified `year`, `month`, and `day` represents a valid date value, and `false` otherwise. Note that valid date values are (as fully defined in the component‐level documentation) in the range `[ 0001/01/01 .. 9999/12/31 ]` (except that `[ 1752/09/03 .. 1752/09/13 ]` are not valid for historical reasons).
| xref:BloombergLP/bdlt/PosixDateImpUtil/isValidYearMonthDayNoCache.adoc[`isValidYearMonthDayNoCache`] 
| Return `true` if the specified `year`, `month`, and `day` represents a valid date value, and `false` otherwise. Note that valid date values are (as fully defined in the component‐level documentation) in the range `[ 0001/01/01 .. 9999/12/31 ]` (except that `[ 1752/09/03 .. 1752/09/13 ]` are not valid for historical reasons). Also note that this function is guaranteed not to use any date‐cache optimizations.
| xref:BloombergLP/bdlt/PosixDateImpUtil/lastDayOfMonth.adoc[`lastDayOfMonth`] 
| Return the last day of the specified `month` in the specified `year`. The behavior is undefined unless `1 <= year <= 9999` and `1 <= month <= 12`. Note that the value returned will be in the range `[ 28 .. 31 ]`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/numLeapYears.adoc[`numLeapYears`] 
| Return the number of leap years occurring between the specified `year1` and `year2` (inclusive). The behavior is undefined unless `1 <= year1 <= 9999`, `1 <= year2 <= 9999`, and `year1 <= year2`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToDay.adoc[`serialToDay`] 
| Return the day (of the month) of the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToDayNoCache.adoc[`serialToDayNoCache`] 
| Return the day (of the month) of the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`. Note that this function is guaranteed not to use any date‐cache optimizations.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToDayOfWeek.adoc[`serialToDayOfWeek`] 
| Return, as an integer (with `1 = SUN`, `2 = MON`, ..., and `7 = SAT`), the day (of the week) of the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToDayOfYear.adoc[`serialToDayOfYear`] 
| Return the day of the year of the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToMonth.adoc[`serialToMonth`] 
| Return the month of the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToMonthNoCache.adoc[`serialToMonthNoCache`] 
| Return the month of the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`. Note that this function is guaranteed not to use any date‐cache optimizations.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToYd.adoc[`serialToYd`] 
| Load, into the specified `year` and `dayOfYear`, the year‐day representation of the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToYear.adoc[`serialToYear`] 
| Return the year of the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToYearNoCache.adoc[`serialToYearNoCache`] 
| Return the year of the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`. Note that this function is guaranteed not to use any date‐cache optimizations.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToYmd.adoc[`serialToYmd`] 
| Load, into the specified `year`, `month`, and `day`, the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToYmdNoCache.adoc[`serialToYmdNoCache`] 
| Load, into the specified `year`, `month`, and `day`, the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`. Note that this function is guaranteed not to use any date‐cache‐optimizations.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ydToDay.adoc[`ydToDay`] 
| Return the day (of the month) of the date value indicated by the specified `year` and `dayOfYear`. The behavior is undefined unless `true == isValidYearDay(year, dayOfYear)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ydToDayOfWeek.adoc[`ydToDayOfWeek`] 
| Return, as an integer (with `1 = SUN`, `2 = MON`, ..., and `7 = SAT`), the day (of the week) of the date value indicated by the specified `year` and `dayOfYear`. The behavior is undefined unless `true == isValidYearDay(year, dayOfYear)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ydToMd.adoc[`ydToMd`] 
| Load, into the specified `month` and `day`, the (partial) calendar date representation of the date value indicated by the specified `year` and `dayOfYear`. The behavior is undefined unless `true == isValidYearDay(year, dayOfYear)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ydToMonth.adoc[`ydToMonth`] 
| Return the month of the date value indicated by the specified `year` and `dayOfYear`. The behavior is undefined unless `true == isValidYearDay(year, dayOfYear)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ydToSerial.adoc[`ydToSerial`] 
| Return the serial date representation of the date value indicated by the specified `year` and `dayOfYear`. The behavior is undefined unless `true == isValidYearDay(year, dayOfYear)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ymdToDayOfWeek.adoc[`ymdToDayOfWeek`] 
| Return, as an integer (with `1 = SUN`, `2 = MON`, ..., and `7 = SAT`), the day (of the week) of the date value indicated by the specified `year`, `month`, and `day`. The behavior is undefined unless `true == isValidYearMonthDay(year, month, day)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ymdToDayOfYear.adoc[`ymdToDayOfYear`] 
| Return the day of the year of the date value indicated by the specified `year`, `month`, and `day`. The behavior is undefined unless `true == isValidYearMonthDay(year, month, day)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ymdToSerial.adoc[`ymdToSerial`] 
| Return the serial date representation of the date value indicated by the specified `year`, `month`, and `day`. The behavior is undefined unless `true == isValidYearMonthDay(year, month, day)`.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ymdToSerialNoCache.adoc[`ymdToSerialNoCache`] 
| Return the serial date representation of the date value indicated by the specified `year`, `month`, and `day`. The behavior is undefined unless `true == isValidYearMonthDay(year, month, day)`. Note that this function is guaranteed not to use any date‐cache optimizations.
|===



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