Re: binder language, binding directories, bind by copy/reference

Joe Pluta wrote:
> 
> AGGHHHHHHHHHHH!
> 
> This is all sooooo cool and I don't quite get it.  Whenever you folks talk
> about this stuff, I ALMOST understand it.  It's like when you ALMOST have to
> sneeze... incredibly frustrating!
> 
> Does anyone have a SIMPLE, real example that I can compile on my machine to
> exemplify the pros and cons of this?  Or if something from one of the
> manuals is best, just point me at it.  I have to be able to touch something
> (and break it <grin>) in order to understand it.  (Hence the piles of
> lawnmower parts in my backyard when I was growing up.)
> 

I know what you mean - I don't really learn something until I get my
hands dirty.  Here's a bnddir example.  (It's as simple as I can make
it, but I don't know about real ... real would make this post WAY WAY
too long instead of just too long :-)

Step 1:

Create 5 source members in qrpglesrc: junkprotos, junksrv, junkpgm,
junkbndsig, junkbndcur

 * This is junkprotos
D proc1           pr                       
D   parm                        10a   const

 * This is junksrv
H nomain                                                    
 /copy junkprotos                                           
D msg             s             52a                         
P proc1           b                   export                
D                 pi                                        
D   parm                        10a   const                 
C                   eval      msg = 'Caller called ' + parm 
C                                 + ' and this is proc1.'   
C     msg           dsply                                   
P                 e                                         

 * This is junkpgm:
 /copy junkprotos                             
C                   callp     proc1 ('proc1') 
C                   eval      *inlr = '1'     

 /* This is junkbndsig */
STRPGMEXP PGMLVL( *CURRENT ) SIGNATURE('JUNK')
  EXPORT SYMBOL( "PROC1"         )           
ENDPGMEXP                                         

 /* This is junkbndcur */
STRPGMEXP PGMLVL( *CURRENT ) SIGNATURE(*GEN)
  EXPORT SYMBOL( "PROC1"         )           
ENDPGMEXP                                         


Step 2: 
===> crtrpgmod junksrv
===> crtrpgmod junkpgm

===> crtsrvpgm junksrvall module(junksrv) export(*all)
===> crtsrvpgm junksrvsig module(junksrv) srcfile(qrpglesrc)
srcmbr(junkbndsig)
===> crtsrvpgm junksrvcur module(junksrv) srcfile(qrpglesrc)
srcmbr(junkbndcur)

===> crtpgm junkpgmall module(junkpgm) bndsrvpgm(junksrvall)
===> crtpgm junkpgmsig module(junkpgm) bndsrvpgm(junksrvsig)
===> crtpgm junkpgmcur module(junkpgm) bndsrvpgm(junksrvcur)

===> call junkpgmall
===> call junkpgmsig
===> call junkpgmcur

All should run successfully and display something like "Caller called
proc1, this is proc1"

Step 3:
- Edit the junkprotos member and add proc2, identical to proc1
- Edit the junksrv member and add proc2, identical to proc2 (don't 
  forget to change the DSPLY line)
- Edit the junkbndsig and junkbndcur files as follows.  (In junkbndsig,
  add a line; in junkbndcur, add a new signature block based on the 
  previous one, and change the previous one to have *PRV.)

 /* This is junkbndsig */
STRPGMEXP PGMLVL( *CURRENT ) SIGNATURE('JUNK')
  EXPORT SYMBOL( "PROC1"         )           
  EXPORT SYMBOL( "PROC2"         )           
ENDPGMEXP                                         

 /* This is junkbndcur */
STRPGMEXP PGMLVL( *CURRENT ) SIGNATURE(*GEN)
  EXPORT SYMBOL( "PROC1"         )          
  EXPORT SYMBOL( "PROC2"         )           
ENDPGMEXP                                         
STRPGMEXP PGMLVL( *PRV ) SIGNATURE(*GEN)
  EXPORT SYMBOL( "PROC1"         )           
ENDPGMEXP                               

Step 4:
This will illustrate that export(*all) is hopeless, and that both the
other methods work fine to allow existing programs to run after a
service program has more procedures added.
- Recreate the junksrv module
- Recreate the three service programs the same way as before (but don't
recreate the programs)
- Call the three programs
  - junkall will fail with a signature violation
  - the other two will run fine (both methods allow existing programs to
run without
    being recreated)

Step 5:
This will illustrate that you have to keep the procedures in the
original order with both binder source styles.
- Edit the junkpgm source and add a line to callp proc2('proc2')
- Recreate the junkpgm module
- Recreate the two junkpgmsig and junkpgmcur the same way as before
- Call these two programs (they should work fine, displaying the correct
call info)
- Now edit junkprotos and junksrv and add proc3 same as the other two
- Edit the binder source as follows, adding the PROC3 before PROC2
instead of after:

 /* This is junkbndsig */
STRPGMEXP PGMLVL( *CURRENT ) SIGNATURE('JUNK')
  EXPORT SYMBOL( "PROC1"         )           
  EXPORT SYMBOL( "PROC3"         )      /* out of order */
  EXPORT SYMBOL( "PROC2"         )           
ENDPGMEXP                                         

 /* This is junkbndcur */
STRPGMEXP PGMLVL( *CURRENT ) SIGNATURE(*GEN)
  EXPORT SYMBOL( "PROC1"         )          
  EXPORT SYMBOL( "PROC3"         )      /* out of order */
  EXPORT SYMBOL( "PROC2"         )           
ENDPGMEXP                                         
STRPGMEXP PGMLVL( *PRV ) SIGNATURE(*GEN)
  EXPORT SYMBOL( "PROC1"         )          
  EXPORT SYMBOL( "PROC2"         )           
ENDPGMEXP                                         
STRPGMEXP PGMLVL( *PRV ) SIGNATURE(*GEN)
  EXPORT SYMBOL( "PROC1"         )           
ENDPGMEXP                               

- recreate the two junksrvcur and junksrvsig service programs as before 
  (but don't recreate the programs)
- call junkpgmcur and junkpgmsig
- the dsply's will show that the programs think they are calling proc2
but 
  they will actually call proc3.
- correct both binder source members to move proc3 after proc2
- recreate the service programs (but not the programs)
- call the programs again - they should be correct

My conclusions:
1. Don't use EXPORT(*ALL).
2. You can't change the order of the exports with either style of binder 
   source, so you might as well use the simple form with the single 
   list of exports.