Re: Question about _Rreadn C function

["Charles Wilt" <charles.wilt@xxxxxxxxx>]

Ok looks like my suspicions where correct, I need something like so:

d p_Ptr                      *   based(p_p_Ptr)
d p_p_Ptr                  *

p_p_Ptr =  recFile.in_buff;

MemMove(myBuff : p_Ptr : 114);

Charles

On Wed, Sep 24, 2008 at 4:51 PM, Charles Wilt <charles.wilt@xxxxxxxxx> wrote:
> Sorry, mixed up source and destination....
>
> should be:
> MemMove(myBuffer : recFile.in_buf : 114);
>
> The code is correct <grin>
>
> Charles
>
> On Wed, Sep 24, 2008 at 4:50 PM, Charles Wilt <charles.wilt@xxxxxxxxx> wrote:
> > Ok another issue.
> >
> > When I try to copy the data out of the buffer, I get garbage.
> >
> > I think perhaps my RPG prototype isn't right or I'm not using it right.
> >
> > here's part of the C structure definition for _RFILE:
> > volatile void  *const *const in_buf;
> > volatile void  *const *const out_buf;
> >
> > Here's the RPG DS definition I'm using:
> >     D   in_buf                        *
> >     D   out_buf                       *
> >
> > I was trying to use in_buf like so:
> > MemMove(fileFile.inbuf : myBuffer : 114)
> >
> > Which apparently isn't right.
> >
> > Is there a way to use _RFILE.in_buf in RPG?
> >
> > Thanks!
> > Charles Wilt
> >
> > On Wed, Sep 24, 2008 at 11:02 AM, Charles Wilt <charles.wilt@xxxxxxxxx> wrote:
> > > All,
> > >
> > > I'm calling the _Rread() C function from RPG (thus the cross-posting).
> > >
> > > _RIOFB_T *_Rreadn (_RFILE *fp, void *buf, size_t size, int opts)
> > >
> > > I'm trying to use the "locate mode" of the function by not passing the
> > > void *buf parameter as I want to move the buffer myself ( via
> > > fp->in_buf) in a later procedure.
> > >
> > > However, my question: how can I determine if an error occurred?
> > > According to the manual:
> > >
> > > "If attempts are made to read beyond the last record in the file, the
> > > num_bytes field is set to EOF. If it is unsuccessful, the num_bytes
> > > field is set to a value less than size, and errno is changed. If you
> > > are using device files and specify zero as the size, check errno to
> > > determine if the function was successful."
> > >
> > > But when in "locate mode" the manual says:
> > > "size Specifies the number of bytes that are to be read and stored in
> > > buf. If locate mode is used, this parameter is ignored."
> > >
> > > So I can still detect EOF, but what about other errors?
> > >
> > > Thanks!
> > > Charles Wilt