Re: C-function returns *NULL when executing malloc

[Patrick Townsend <patrick.townsend@xxxxxxxxxxxxxx>]

Hi Birgitta,
On the first call to malloc the memory gets assigned to the popinter
value. On subsequent calls where the pointer is already defined you
would need to use realloc. But I don't think that is what you want to
do. In C you would look at the global variable errno to determine the
cause. See member errno in file h in library qsysinc.
Chiuss,
Patrick

On 9/16/09, Birgitta Hauser <Hauser@xxxxxxxxxxxxxxx> wrote:
> Hi,
>
>
>
> someone has an idea what happens?
>
>
>
> If have to call a procedure written in RPG (but by a C-Programmer).
>
> Within this procedure a local data structure is defined with based(Pointer).
>
> The first statement within this procedure calls the procedure malloc to
> allocate storage and to get a pointer on this storage.
>
> After memset is used to initialize this storage.
>
>
>
> D  MyDS                      DS
> Based(MyDS_p)
>
> D . . . Datastructure Subfields
>
>
>
> D  MyPtr                    S                                  *
>
>  /Free
>
>      MyDS_p  = malloc(%Size(MyDS));
>
>      memset(MyDS_p: 0: %Size(MyDS));
>
>     …..
>
>
>
>  /End-Free
>
>
>
> In an specific environment it works the first time I call the procedure, but
> for all subsequent calls MyDS_p is returned as  *NULL-Value (and I have no
> idea why, there is no joblog entry either ).
>
> If I call the same procedure from an other program within the same job it
> works without problems, even for repeated calls.
>
>
>
> I know it would be easier to define the data structure directly without
> based, but it is an old procedure and I cannot change it.
>
>
>
> Someone has an idea what happened.
>
> My colleague assumes it is because I’m using named activation groups, while
> all other programs and service program (also this one where the procedure is
> located) run in the QILE default activation group.
>
> But I cannot imagine that different activation groups may cause this
> problem.
>
>
>
> Mit freundlichen Grüßen / Best regards
>
>
>
> Birgitta Hauser
>
>
>
> "Shoot for the moon, even if you miss, you'll land among the stars." (Les
> Brown)
>
> "If you think education is expensive, try ignorance." (Derek Bok)
>
> "What is worse than training your staff and losing them? Not training them
> and keeping them!"
>
>
>
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