• Subject: Re: Operational descriptors
  • From: David Morris <dmorris@xxxxxxxxxxxxx>
  • Date: Wed, 18 Mar 1998 13:54:24 -0700

I may have found the answer to my first question.  The manual says "Static 
calls 
allow operational descriptors..." implying that a non bound call cannot pass 
operational 
descriptors.

This probably seems obvious to the guy who wrote the compiler but I am still
unsure about the correct way to prototype a main procedure.  How does the 
compiler 
determine the export name?  The manual says "If EXTPGM is specified, then an 
external program call is 
used; if EXTPROC is specified or if neither keyword is specified, it will be 
called by using a 
procedure call."   I can't display a program and see the procedure exports, so 
how do I 
determine what name is used?  Is it the uppercase name specified for the 
procedure interface and 
prototype?   Main was probably not a good idea because of the possibility of 
duplicate exports.

The loop that I found when you specify Begin and End procedure statements 
should have been 
caught by the compiler.  The manual says "...only procedure with a complete set 
of specifications 
available (except the P specification)"  implying that "P" specs are not 
allowed.  It does seem 
odd that you can't code a begin or end procedure just because it is a main 
procedure.  Kind of 
like not allowing ProcNam() when no parameters are passed.

The manual also says "You cannot define return values for a main procedure, 
nor can you specify that its parameters be passed by value."  Why doesn't the 
compiler check for this, or is this incorrect?

Thanks,

David Morris

>>> David Morris <dmorris@plumcreek.com> 03/16 6:02 PM >>>
Can anyone tell me how to specify operational descriptors for a main procedure. 
 I have 
OPDESC on the prototype and procedure interface but get an error "operational 
descriptors 
not passed" when the program is called.  Is this because you can't pass 
operational 
descriptors to a main procedure?   This procedure is an OPM interface to a 
sub-procedure 
that receives highly variable parms.  I have found that callprc to a 
sub-procedure does 
pass operational descriptors.  I may just have to use %len(%trimr()) to set the 
length and 
require that they be declared at the maximum width in OPM programs.  
%len(%trimr()) for a 
long field takes a hemosecond to execute.

Can anyone tell me the "correct" way to specify a main procedure with a 
prototype?  The 
manual is vague.  I have settled on the name Main for the prototype and 
procedure 
interface.  I also found a that a main procedure will loop if you specify a 
begin and 
end procedure.  Found that through trial and error while trying to get the 
OPDESC to 
work.  This means that a main procedure cannot be used as a sub-procedure.

One more question.  What is the best way to pass omittable parms through a 
program?  
I don't understand why a parameter passed by reference can't just be passed 
through 
to a another procedure with the associated descriptors, etc. intact.  Is there 
a trick?  
All I get is a reference to a parameter not passed.  Depending on the number of 
omittable parameters I have had to code up to 25 different calls in a case 
statement.  In 
another case I had to use subroutines and copy source because there would have 
been hundreds of possible combinations.

Thanks,

David Morris
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                       
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