[#BloombergLP-bdlt-PosixDateImpUtil-serialToDay] = xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlt.adoc[bdlt]::xref:BloombergLP/bdlt/PosixDateImpUtil.adoc[PosixDateImpUtil]::serialToDay :relfileprefix: ../../../ :mrdocs: Return the day (of the month) of the date value indicated by the specified `serialDay`. The behavior is undefined unless `true == isValidSerial(serialDay)`. == Synopsis Declared in `<bdlt_posixdateimputil.h>` [source,cpp,subs="verbatim,replacements,macros,-callouts"] ---- static int serialToDay(int serialDay); ---- [.small]#Created with https://www.mrdocs.com[MrDocs]#