Use the QWCCVTDT API.
In the feature story in this issue ("When Was
I Born?"), the RTVSBMJOBA command took advantage of the QWCCVTDT API. If you have character text that is used as a date value, this API allows you to convert
it from one date format to another. The API will also retrieve the current
system date and time for you.
The QWCCVTDT API is a program (not a procedure call), but it seems to run
fairly fast. To use it, you need to prototype it, convert your date values into
character format without embedded date separators, and pass the API your date
and the format in which it is stored.
Here is the prototype for the QWCCVTDT API:
D QWCCVTDT PR ExtPgm('QWCCVTDT') D inFmt 10A Const OPTIONS(*VARSIZE) D inDate 64A Const OPTIONS(*VARSIZE) D outFmt 10A Const OPTIONS(*VARSIZE) D outDate 64A OPTIONS(*VARSIZE) /IF DEFINED(*V5R1M0) D api_error LikeDS(QUSEC) /ELSE D api_error Like(QUSEC) D/ENDIF
The following illustrates how to call the QWCCVTDT API.
D FromDate DS LikeDS(CvtDT17_T) D ToDate DS LikeDS(CvtDT16_T) D Today S D Inz(*SYS) D JobDate S 6S 0 C eval FromDate.szDate17_cvt = %char(Today:*ISO0)
C C callp QwcCvtDT('*YYMD':FromDate:'*JOB':ToDate) C eval JobDate = %Int(ToDate.szDate16_cvt)
In this example, the system date is automatically stored in the field named
TODAY. That date is converted to character and copied into the szDate17_cvt
subfield. Then, the date is converted to the job's date format by QWCCVTDT and
copied into the JOBDATE field. This is an obviously contrived example that ends
up with JOBDATE containing effectively the same value as UDATE, with one
exception. UDATE is static and never changes, whereas the INZ(*SYS) on the TODAY
field causes the current system clock date to be used.
The input date and return date parameters have a special format that includes
the time down to the milliseconds. The data structures for the two classes of
date format are as follows:
********************************************************** ** Data structure of the data input to and returned from ** the QWCCVTDT API. This 16-byte structure is use for ** date formats: *JOB *SYSVAL *YMD *MDY *DMY and *JUL ********************************************************** D CvtDT16_T DS
D nCent16_cvt 1A
D szDate16_cvt 6A
D szTime16_cvt 6A
D szMS16_cvt 3A
********************************************************** ** Data structure of the data input to and returned from ** the QWCCVTDT API. This 17-byte structure is use for ** date formats: *YYMD *MDYY *DMYY and *LONGJUL **********************************************************
D CvtDT17_T DS
D szDate17_cvt 8A
D szTime17_cvt 6A
D szMS17_cvt 3A
The date is the only thing that is variable in these two data structures. The
szTime16_cvt and szTime17_cvt subfields always contain the time in HHMMSS
format, using a 24-hour clock.
QWCCVTDT is a simple, yet useful API to convert dates from one format to
another. While the API requires character parameters, your implementation could
define the date subfields in the two data structures as numeric.
Bob Cozzi is a programmer/consultant,
writer/author, and software developer. His popular RPG xTools add-on
subprocedure library for RPG IV is fast becoming a standard with RPG developers.
His book The Modern RPG
Language has been the most widely used RPG programming
book for more than a decade. He, along with others, speaks at and produces the
highly popular RPG
World conference for RPG
programmers. |