Oppolzer - Informatik / Blog

There is an error in the definition of STRUCT,
the INIT (15) after V1 should be omitted, the correct definition is

  DCL 1 STRUCT,
        3 V1 BIN FIXED (31),
        3 V2 BIN FIXED (31);

Sorry

Bernd



Am 23.03.2014 11:31, schrieb Bernd Oppolzer:
> Hi Z.,
>
> I'd like to start with the following source:
>
>
>  DCL TESTPLI EXTERNAL ENTRY
>      (PTR,                     /* ADDR (CHAR) */
>       BIN FIXED (31),
>       PTR);                    /* ADDR (PCRE) */
>
>  DCL PARMC  CHAR (20)        INIT ('ENTRY VALUE');
>  DCL PARMI  BIN FIXED (31)   INIT (15);
>  DCL 1 STRUCT,
>        3 V1 BIN FIXED (31),  INIT (15);
>        3 V2 BIN FIXED (31);
>
>  PUT SKIP LIST (PARMC);
>  PUT SKIP LIST (PARMI);
>
>  CALL TESTPLI (ADDR (PARMC),
>                PARMI,
>                ADDR (STRUCT));
>
>  PUT SKIP LIST (PARMC);
>  PUT SKIP LIST (PARMI);
>
>
>
>
> /**************************************/
> /*  Test C interface to PL1           */
> /**************************************/
>
> int testpli (const char **p1,
>              int *p2,
>              void **p6)
>
> {
>    char buffer [21];
>    int intfield;
>
>    memcpy (buffer, *p1, 20);
>    buffer [21] = 0x00;
>    printf ("%s\n", buffer);
>    memset (*p1, ' ', 20);
>    memcpy (*p1, "RETURN VALUE", 12);
>
>    intfield = *p2;
>    printf ("%d\n", intfield);
>    *p2 = 13;
>
>    return 27;
> }
>
>
> you would have to put the PL/1 excerpts on the top
> into your PL/1 caller and the C test function maybe needs
> some ANSI #includes to make it complete.
>
> Regarding your request, there are some limitations;
>
> because you use an old compiler, you will not be able
> to pass integers by value and char * without descriptors
> (only by using nasty workaround). That's why I limited the
> example above to int * and char **. I showed in the C function
> how to deal with those parameter types. The parameter passed
> is printed in the C function, then changed, and then printed again
> on the PL/1 side.
>
> Another topic here is, that the PL/1 char in this case is not
> null-terminated, but the C function like prints expects a
> null termination, so the C function adds a zero byte.
> That might not be necessary in your PCRE case, or:
> it could be the other way round, that is: the PL/1 side has
> to take care to add the zero byte.
>
> I would encourage you to test these code snippets, and once
> you are convinced that they work, then we go ahead and
> work again on your PCRE project. The problems that you sent
> me offline IMHO have nothing to do with the parameter passing
> mechanism.
>
> Kind regards
>
> Bernd
>
>
>
>
> Am 23.03.2014 08:07, schrieb Z.A.:
>> Hi All
>> Does any of you have a working example in which the PL/1 calls a C
>> function with any of these parameters
>>
>> char * varname
>> char ** varname
>> int varname
>> int * varname
>> sometype * varname
>>
>> and this routine returns any of
>> int
>> char *
>> sometype *
>>
>> Especially, I am interested in cases where the C is NOT aware of any
>> descriptor while the PL/1 is compiled in most common way.  I am not
>> interested in the theory, I tried to work with the theory to no
>> avail.  I really need to see a working example (relevant snippets)
>> ideally, i would like to see both sides behavior (i.e. how the PL/1
>> calling using any specific signature and how the C is handling that
>> parm.
>>
>> Any response would be highly appreciated.
>>
>> Thanks
>>
>> ZA
>>
>
>