Re: Converting packed decimal to a char array

I want to point out that while the MI reference has not been available as a
PDF for quite some time, the html documentation still exists in the IBM i
knowledge center and is updated with each release of IBM i.  For the most
current version of MI reference documentation you need to go to the IBM i
knowledge center for your release and then select 'Programming->Application
programming interfaces->Machine interface programming' (6.1 & 7.1) or
'Programming->Application programming interfaces->IBM i Machine
Interface' (7.2).


Aaron Albertson


"C400-L" <[email protected]> wrote on 01/10/2015 10:52:02 AM:

> From: Jon Paris <[email protected]>
> To: "C400-L@Midrange. Com" <[email protected]>
> Date: 01/10/2015 10:52 AM
> Subject: Re: [C400-L] Converting packed decimal to a char array
> Sent by: "C400-L" <[email protected]>
>
> You can use the functions you have found but it is more work that
> you need I suspect. In some cases sprintf might be enough since the
> additional formatting option D(n,p) is available. The MI built-ins
> can also provide alternative approaches for some of these functions.
> For example EDIT_PACKED does a high speed conversion of a packed
> source to an external character form.
>
> These are all listed in the MI reference http://www-01.ibm.com/
> support/knowledgecenter/api/content/nl/en-us/ssw_i5_54/books/sc092418.pdf
> - this seems to be the latest version but not sure. Each of the
> definitions includes an example of calling the function from C.
>
> Sorry I don’t understand your comment at the end regarding the
> returned structures. Do you have an RPG definition of them we could
> look at - it would make it easier to see what you are trying to do.
> For example you said "The input and outputs are both data buffers
> that are effectively packed structures” but for us the word “packed”
> has meaning as referencing a type of numeric field. I’m thinking
> that when you say “packed” you mean struct with not separators
> between the fields?
>
> An RPG definition of a struct (known as a DS) incorporating a packed
> numeric might look like this:
>
>      d results         ds
>      d  char                         10a     // 10 character char array
>      d  pkd1                          9p 2   // 7.2 packed decimal -
> occupies 5 bytes
>                                              // sign is in rightmost
nyble
>      d  zoned1                        9s 2   // 7.2 zoned numeric -
> occupies 10 bytes
>                                              // sign is high order
> bit settings in rightmost byte
>
> If you can show us the structure you are dealing with it would be a
> lot easier to help you. I’m not a C programmer - I know just enough
> to be really dangerous - but I know RPG!
>
>
> Jon Paris
>
> www.partner400.com
> www.SystemiDeveloper.com
>
> On Jan 10, 2015, at 5:56 AM, Jevgeni Astanovski <[email protected]>
wrote:
>
> > Thanks, Jon.
> >
> > Well, by now I found these editing function and got the following:
> >
> >  decimal (15,0) A = 125678D ;
> >  char szTemp[256], szOutput[256], EditMask[256], ZeroFill[1] ;
> >  int n, m, MaskLen, RcvLen ;
> >  Qus_EC_t error_code ;
> >
> >  n = digitsof(A) ;
> >  m = precisionof(A) ;
> >
> >  QECCVTEC(EditMask, &MaskLen, &RcvLen, ZeroFill, "P", " ", n, m,
> >           &error_code) ;
> >
> >  QECEDT(szTemp, RcvLen, &A, "*PACKED   ", n, EditMask, MaskLen, "0",
> >           &error_code) ;
> >  memcpy(szOutput, szTemp, RcvLen) ;
> >  szOutput[RcvLen] = 0x00 ;
> >  printf("After conversion A: !%s!\n", szOutput) ;
> >
> >
> > It produces the following:
> > After conversion A: !          125678!
> > What I expected is a number padded with zeros in the left.
> > I have to check if the receiver program will accept the changed
input...
> >
> > Is it what you meant in your advise?
> >
> > You asked what for do I need it.
> > I have a big set of API-s on iSeries that are called via RPC from PC
> > environment. The input and outputs are both data buffers that are
> > effectively packed structures - that is data fields without any
> > separators with known widths. This is as infrastructure and I cannot
> > change it. Packed numbers are always returned as char arrays - and it
> > is also part of the infrastructure....
> >
> >
> >
> > On Fri, Jan 9, 2015 at 5:47 PM, Jon Paris <[email protected]>
wrote:
> >> It would help to know why you are trying to do this (editing the
> number for example?).
> >>
> >> Have you looked at the various editing and conversion
> capabilities available in the surfaced MI functions (https://
> publib.boulder.ibm.com/iseries/v5r1/ic2924/books/c0924180.pdf) as
> well as the C/C++ library extensions? (http://www-01.ibm.com/
> support/knowledgecenter/#!/ssw_ibm_i_72/rtref/rtrefmain.htm).
> >>
> >> Everything you could need is there.
> >>
> >>
> >> Jon Paris
> >>
> >> www.partner400.com
> >> www.SystemiDeveloper.com
> >>
> >> On Jan 9, 2015, at 4:00 AM, Jevgeni Astanovski
> <[email protected]> wrote:
> >>
> >>> Hi all,
> >>>
> >>> spend a lot of time and feeling like I run into a dead cycle with a
> >>> problem, that looks trivial.
> >>>
> >>> I have packed decimals in my C programs that I need to convert to a
> >>> char array, representing the number (not zero terminated string).
> >>>
> >>> For example:
> >>>
> >>> decimal (15,9) A ;
> >>> char szTemp[32], sField[16] ;
> >>>
> >>> sprintf(szTemp, "%016D(15,9)", A) ;
> >>> memcpy(sField, szTemp, 16) ;
> >>>
> >>> What I want to achieve is get a function, that receives A and
> returns sField.
> >>> Of course it must support any types of decimal - not only decimal
> >>> (15,9) but others like decimal(11,7), decimal (15,0), decimal (5,0)
> >>> and so on. And, of course, decimal can be positive or negative...
> >>>
> >>>
> >>> Any ideas?
> >>>
> >>> Jevgeni.
> >>> --
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