Re: Using CL to call RPG pgms

[Tony Carolla <carolla@xxxxxxxxx>]

I personally don't use CL in any new projects. I actually just re-wrote my 
initial program in RPG, using APIs. ;-)

Here's how I handle the stuff. First of all, system() is much easier to use 
than QCMDEXC, in my opinion. In case you haven't used it, you prototype it 
as follows: 

D system PR 10I 0 ExtProc('system')
D szCmd * Value
D Options(*String)

D RC S 10I 0 Inz

Then, you can use it as follows:

RC=system('CRTPF ...');

If RC=0, the command was successful. There are more options for checking the 
detailed error (see many posts on system())

For specifying which library to find files in (rather than using OVRDBF), I 
use the EXTFILE keyword on the F-specs, that tells exactly what library/file 
to open. You can even use a variable, and set the file as USROPN. Then, in 
your calcs, resolve the variable and open the file. If you need to hit the 
file in multiple places, close it, re-resolve the variable, and open it 
again. Of course, when you compile, your current library list is searched 
for the file, but once compiled, you are in the driver's seat as to which 
file to actually open. 

Another thing to consider is the use of APIs. When you are using system() or 
QCMDEXC to run a CL Command, often times the CL command runs a program that 
uses APIs to perform the action. For these, it might be beneficial to just 
prototype the API, and call it from within the RPG program. I wrote a 
program that displays field level details, in a much more abbreviated 
fashion than DSPFFD, and rather than use DSPFFD to an outfile, I used 
QUSLRCD, QUSLFLD and QDBRTVFD (to get key data) directly. It is very fast. 

But some might say that this approach is too complex, when you can simply 
issue a CL command. 


On 9/2/05, Igor.Beslic@xxxxxxxxxxxx <Igor.Beslic@xxxxxxxxxxxx> wrote:
> 
> Hello!
> 
> I have almost 1,5 year expirience in ILE RPG IV and now I realized that
> almost evry RPG pgm I've made needed additional CL pgm that shold prepare
> LIBL, clear output PFs and perform similar actions after pgm finises...
>