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

Namespace for low‐level POSIX‐calendar date conversion utilities.

== Synopsis

Declared in `<bdlt_posixdateimputil.h>`

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

== Description

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.

== 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 whether `serialDay` is a valid serial date value.
| xref:BloombergLP/bdlt/PosixDateImpUtil/isValidYearDay.adoc[`isValidYearDay`] 
| Return whether `year` and `dayOfYear` form a valid date.
| xref:BloombergLP/bdlt/PosixDateImpUtil/isValidYearMonthDay.adoc[`isValidYearMonthDay`] 
| Return whether `year`/`month`/`day` is a valid POSIX calendar date.
| xref:BloombergLP/bdlt/PosixDateImpUtil/isValidYearMonthDayNoCache.adoc[`isValidYearMonthDayNoCache`] 
| Return whether YMD is valid without using the date cache.
| xref:BloombergLP/bdlt/PosixDateImpUtil/lastDayOfMonth.adoc[`lastDayOfMonth`] 
| Return the last day of month for the given year and month.
| xref:BloombergLP/bdlt/PosixDateImpUtil/numLeapYears.adoc[`numLeapYears`] 
| Return the number of leap years between `year1` and `year2` inclusive.
| 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 month for `serialDay` without using the date cache.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToDayOfWeek.adoc[`serialToDayOfWeek`] 
| Return the day of week (1=SUN .. 7=SAT) for the given serial day.
| 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 for `serialDay` without using the date cache.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToYd.adoc[`serialToYd`] 
| Load year and day‐of‐year from the given serial day.
| 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 for `serialDay` without using the date cache.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToYmd.adoc[`serialToYmd`] 
| Load year, month, and day from the given serial day.
| xref:BloombergLP/bdlt/PosixDateImpUtil/serialToYmdNoCache.adoc[`serialToYmdNoCache`] 
| Load YMD from `serialDay` without using the date cache.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ydToDay.adoc[`ydToDay`] 
| Return the day of month for the given year and day‐of‐year.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ydToDayOfWeek.adoc[`ydToDayOfWeek`] 
| Return the day of week (1=SUN .. 7=SAT) for year and day‐of‐year.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ydToMd.adoc[`ydToMd`] 
| Load month and day from the given year and day‐of‐year.
| 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 for the given year and day‐of‐year.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ymdToDayOfWeek.adoc[`ymdToDayOfWeek`] 
| Return the day of week (1=SUN .. 7=SAT) for the given YMD date.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ymdToDayOfYear.adoc[`ymdToDayOfYear`] 
| Return the day of year for the given year, month, and day.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ymdToSerial.adoc[`ymdToSerial`] 
| Return the serial date for the given year, month, and day.
| xref:BloombergLP/bdlt/PosixDateImpUtil/ymdToSerialNoCache.adoc[`ymdToSerialNoCache`] 
| Return the serial date for YMD without using the date cache.
|===



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