RE: ILE C/400 calling RPGLE

You have 5I0 which is a "short" in C, not an "int".
-Bob


-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of Chris Wolcott
Sent: Monday, March 29, 2004 1:20 PM
To: rpg400-l@xxxxxxxxxxxx
Subject: ILE C/400 calling RPGLE

I've tried to find this on the web and in the archives, but all I can
find is RPG calling C, not the other way around.  I can't find ANYTHING
on the way parms are handled in each language.  (I thought I'd read that
RPG always passes by reference, but C by default passes by value, but I
can not seem to be able to verify that.)  

In 'C' I'd have to allocate memory to return a value, else the associate
memory goes away when the call is over and would give me such an MCH3601
error.  The allocated section of memmory is 'lost' until the job
terminates or it is expressly FREE'd.  If the code is called multiple
times, you start to lose memory.  How does RPG get around this? 

QUESTION:

I have applications in both ILE C/400 and RPGLE.  I'm trying to write a
SRVPGM in RPG that is callable by either language.  (I am more
comfortable in RPG than C.)  For returning an integer, I can define the
prototype to be '5I 0' and it works fine.  However, when I try to return
a string from RPG to a C program I get an MCH3601 - Pointer not set for
location referenced.  (It gets the parms and does all the work, it fails
on the RETURN statement.)  The routine works fine for other RPGLE and
CLLE programs.  What am I doing wrong?



RPG: D MYFUNCT1        PR             5I 0       
     D   PARM1                       15A   CONST 
(Accepting a 15 character value and returning an INTEGER value)

RPG: D MYFUNCT2        PR             4A        
     D   PARM1                       15A   CONST
(Accepting a 15 character value and returning a 4 byte HEX value)

C:   int           MYFUNCT1(char *);  <- NOTE: NOT a pointer!?

C:   unsigned int *MYFUNCT2(char *);  
(Unsigned Integers are 4 bytes long, same as the 4 char field in RPG.  I
have a C routine called by RPG that treats them both this same way and
it works.)

 

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