Re: RETURN value from a REXX Procedure

Dave,

What you described below could be implemented with a "pre-processor" of ILE RPG IV, (that could itself even be written in REXX) ...  The idea is, read that "prototype" and generate equivalent ILE RPG IV (or even ILE CL or ILE C) and include or compile that "stub" to provide the interface, so that it is bound into your program, to do the job of invoking STRREXPRC, when that HLL "procedure" is invoked.  Due to lack of any direct support for "RETURN value" via STRREXPRC, the preprocessor must select a method to return values to "the outside." 


REXX can easily CALL various APIs, such as QSNDDTAQ and QRCVDTAQ, or the "user space" APIs, to manipulate the contents of a user space, so you could store the result, even a quite large result, in a data queue or user space, and then upon return, the generated interface "stub" would know where to find the result, and "pull" the result from the data queue or user space.  (For a smaller result, up to 2000 bytes, you could even use a simple data area, and REXX can just invoke the CHGDTAARA command.)


A clever preprocessor could even process the REXX source code to transform the "RETURN value" statement to  usethe desired interface, e.g.  data area, data queue or user space, etc.


Just saying ...

Mark S. Waterbury



On Tuesday, August 20, 2019, 4:17:06 PM EDT, <dlclark@xxxxxxxxxxxxxxxx> wrote:
...(snip)...
        I'd like to see a prototype such as the following supported in
RPG/ILE -- allowing, of course, that the REXX RETURN instruction is
supported for passing a value back to the caller.


dcl-pr MyRexxProcedure char(3000) extproc(*REXX:member:srcfile:library);
  rexxparms  char(3000)      options(*nopass);
  initcmdenv  char(20)        options(*nopass);
  exitpgmlist char(22) dim(8) options(*nopass);
end-pr;


Sincerely,

Dave Clark