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harbour-core/harbour/doc/en/datetime.txt

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/*
* $Id$
*/
/*
* The following parts are Copyright of the individual authors.
* www - http://www.harbour-project.org
*
* Copyright 2000 Luiz Rafael Culik <culik@sl.conex.net>
* Documentation for: CDOW(),CMONTH(),DATE(),CTOD(),DAY(),DAYS()
* DOW(),DTOS(),DTOC(),ELAPTIME(),MONTH(),SECONDS(),SECS(),TIME(),YEAR()
* See doc/license.txt for licensing terms.
*
*/
/* $DOC$
* $FUNCNAME$
* CDOW()
* $CATEGORY$
* Date
* $ONELINER$
* Converts a date to the day of week
* $SYNTAX$
* CDOW(<dDate>) --> cDay
* $ARGUMENTS$
* <dDate> Any date expression.
* $RETURNS$
* <cDay> The current day of week.
* $DESCRIPTION$
* This function returns a character string of the day of the week,
* from a date expression <dDate> passed to it.
* If a NULL date is passed to the function, the value of the function
* will be a NULL byte.
* $EXAMPLES$
* ? CDOW(DATE())
* if CDOW(DATE()+10) =="SUNDAY"
* ? "This is a sunny day."
* Endif
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant.
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* DAY(),DOW(),DATE(),CMONTH()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* CMONTH()
* $CATEGORY$
* Date
* $ONELINER$
* Return the name of the month.
* $SYNTAX$
* CMONTH(<dDate>) --> cMonth
* $ARGUMENTS$
* <dDate> Any date expression.
* $RETURNS$
* <cMonth> The current month name
* $DESCRIPTION$
* This function returns the name of the month (January,February,etc.)
* from a date expression <dDate> passed to it.
* If a NULL date is passed to the function, the value of the function
* will be a NULL byte.
* $EXAMPLES$
* ? CMONTH(DATE())
* if CMONTH(DATE()+10) =="March"
* ? "Have you done your system BACKUP?"
* Endif
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* CDOW(),DATE(),MONTH(),YEAR(),DOW(),DTOC()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* DATE()
* $CATEGORY$
* Date
* $ONELINER$
* Return the Current OS Date
* $SYNTAX$
* DATE() --> dCurDate
* $ARGUMENTS$
* None
* $RETURNS$
* <dCurDate> Current system date.
* $DESCRIPTION$
* This function returns the current system date.
* $EXAMPLES$
* ? Date()
* $TESTS$
* ? "Today is ",Day(date())," of ",cMonth(date())," of ",Year(date())
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper Compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* CTOD(),DTOS(),DTOC(),DAY(),MONTH(),CMONTH()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* CTOD()
* $CATEGORY$
* Date
* $ONELINER$
* Converts a character string to a date expression
* $SYNTAX$
* CTOD(<cDateString>) --> dDate
* $ARGUMENTS$
* <cDateString> A character date in format 'mm/dd/yy'
* $RETURNS$
* <dDate> A date expression
* $DESCRIPTION$
* This function converts a date that has been entered as a character
* expression to a date expression.The character expression will be in
* the form "MM/DD/YY" (based on the default value in SET DATE) or in
* the appropriate format specified by the SET DATE TO command. If an
* improper character string is passed to the function,an empty date
* value will be returned.
* $EXAMPLES$
* ? CTOD('12/21/00')
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* SET DATE,DATE(),DTOS()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* DAY()
* $CATEGORY$
* Date
* $ONELINER$
* Return the numeric day of the month.
* $SYNTAX$
* DAY(<cDate>) --> nMonth
* $ARGUMENTS$
* <cDate> Any valid date expression.
* $RETURNS$
* <nMonth> Numeric value of the day of month.
* $DESCRIPTION$
* This function returns the numeric value of the day of month from a
* date.
* $EXAMPLES$
* ? Day(DATE())
* ? Day(DATE()+6325)
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* CTOD(),DTOS(),DTOC(),DATE(),MONTH(),CMONTH()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* DAYS()
* $CATEGORY$
* Date
* $ONELINER$
* Convert elapsed seconds into days
* $SYNTAX$
* DAYS(<nSecs> ) --> nDay
* $ARGUMENTS$
* <nSecs> The number of seconds
* $RETURNS$
* <nDay> The number of days
* $DESCRIPTION$
* This function converts <nSecs> seconds to the equivalent number
* of days; 86399 seconds represents one day, 0 seconds being midnight.
* $EXAMPLES$
* ? DAYS(2434234)
* ? "Has been passed ",DAYS(63251),' since midnight'
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* SECONDS(),SECS(),ELAPTIME()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* DOW()
* $CATEGORY$
* Date
* $ONELINER$
* Value for the day of week.
* $SYNTAX$
* DOW(<dDate>) --> nDay
* $ARGUMENTS$
* <dDate> Any valid date expression
* $RETURNS$
* <nDay> The current day number
* $DESCRIPTION$
* This function returns the number representing the day of the week
* for the date expressed as <dDate>.
* $EXAMPLES$
* ? DOW(DATE())
* ? DOW(DATE()-6584)
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* DTOC(),CDOW(),DATE(),DTOS(),DAY()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* DTOC()
* $CATEGORY$
* Date
* $ONELINER$
* Date to character conversion
* $SYNTAX$
* DTOC(<dDateString>) --> cDate
* $ARGUMENTS$
* <dDateString> Any date
* $RETURNS$
* <dDate> Character represention of date
* $DESCRIPTION$
* This function converts any date expression (a field or variable)
* expressed as <dDateString> to a character expression in the default
* format "MM/DD/YY". The date format expressed by this function is
* controled in part by the date format specified in the SET DATE
* command
* $EXAMPLES$
* ? DTOC(Date())
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* SET DATE,DATE(),DTOS()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* DTOS()
* $CATEGORY$
* Date
* $ONELINER$
* Date to string conversion
* $SYNTAX$
* DTOS(<dDateString>) --> cDate
* $ARGUMENTS$
* <dDateString> Any date
* $RETURNS$
* <dDate> String notation of the date
* $DESCRIPTION$
* This function returns the value of <dDateString> as a character
* string in the format of YYYYMMDD. If the value of <dDateString> is
* an empty date, this function will return eight blank spaces.
* $EXAMPLES$
* ? DTOS(Date())
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* DTOC(),DATE(),DTOS()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* ELAPTIME()
* $CATEGORY$
* Time
* $ONELINER$
* Calculates elapted time.
* $SYNTAX$
* ELAPTIME(<cStartTime>,<cEndTime>) --> cDiference
* $ARGUMENTS$
* <cStartTime> Start in time as a string format
* <cEndTime> End time as a string format
* $RETURNS$
* <cDiference> Difference between the times
* $DESCRIPTION$
* This function returns a string that shows the difference between
* the starting time represented as <cStartTime> and the ending time
* as <cEndTime>. If the stating time is greater then the ending
* time, the function will assume that the date changed once.
* $EXAMPLES$
* Static cStartTime
* Init Proc Startup
* cStartTime:=Time()
*
* Exit Proc StartExit
* ? "You used this program by",ELAPTIME(cStartTime,Time())
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* SECS(),SECONDS(),TIME(),DAY()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* MONTH()
* $CATEGORY$
* Date
* $ONELINER$
* Converts a date expression to a month value
* $SYNTAX$
* MONTH(<dDate>) --> nMonth
* $ARGUMENTS$
* <dDate> Any valid date expression
* $RETURNS$
* <nMonth> Corresponding number of the month in the year, ranging from
* 0 to 12
* $DESCRIPTION$
* This function returns a number that represents the month of a given
* date expression <dDate>. If a NULL date (CTOD('')) is passed to the
* function, the value of the function will be 0.
* $EXAMPLES$
* ? Month(DATE())
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* CDOW(),DOW(),YEAR(),CMONTH()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* SECONDS()
* $CATEGORY$
* Time
* $ONELINER$
* Returns the number of elapsed seconds past midnight.
* $SYNTAX$
* SECONDS() --> nSeconds
* $ARGUMENTS$
* None
* $RETURNS$
* <nSeconds> Number of seconds since midnight
* $DESCRIPTION$
* This function returns a numeric value representing the number of
* elapsed seconds based on the current system time.
* The system time is considered to start at 0 (midnight);it continues
* up to 86399 seconds.The value of the return expression is displayed
* in both seconds and hundredths of seconds.
* $EXAMPLES$
* ? Seconds()
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* TIME()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* SECS()
* $CATEGORY$
* Time
* $ONELINER$
* Return the number of seconds from the system date.
* $SYNTAX$
* SECS( <cTime> ) --> nSeconds
* $ARGUMENTS$
* <cTime> Character expression in a time string format
* $RETURNS$
* <nSeconds> Number of seconds
* $DESCRIPTION$
* This function returns a numeric value that is a number of elapsed
* seconds from midnight based on a time string given as <cTime>.
* $EXAMPLES$
* ? Secs(Time())
* ? Secs(time()-10)
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* SECONDS(),ELAPTIME(),TIME()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* TIME()
* $CATEGORY$
* Time
* $ONELINER$
* Returns the system time as a string
* $SYNTAX$
* TIME() --> cTime
* $ARGUMENTS$
* None
* $RETURNS$
* <cTime> Character string representing time
* $DESCRIPTION$
* This function returns the system time represented as a character
* expression in the format of HH:MM:SS
* $EXAMPLES$
* ? Time()
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* DATE(),SECONDS()
* $END$
*/
/* $DOC$
* $FUNCNAME$
* YEAR()
* $CATEGORY$
* Date
* $ONELINER$
* Converts the year portion of a date into a numeric value
* $SYNTAX$
* YEAR(<cDate>) --> nYear
* $ARGUMENTS$
* <dDate> Any valid date expression
* $RETURNS$
* <nYear> The year portion of the date.
* $DESCRIPTION$
* This function returns the numeric value for the year in <dDate>.
* This value will always be a four-digit number and is not affected
* by the setting of the SET CENTURY and SET DATE commands. Addition
* ally, an empty date expression passed to this function will yield
* a zero value.
*
* $EXAMPLES$
* ? Year(date())
* ? year(CTOD("01/25/3251"))
* $STATUS$
* R
* $COMPLIANCE$
* This function is Ca-Clipper compliant
* $PLATFORMS$
* All
* $FILES$
* Library is rtl
* $SEEALSO$
* DAY(),MONTH()
* $END$
*/