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I'm trying to read asynchronously from a file using aio_read:

/* async I/O structures */
struct aiocb cb;
const struct aiocb* list[1] = { &cb };
int aioRet;

/* set appropriate values in control buffer */
cb.aio_fildes = fromfd;
cb.aio_buf = buffer0;
cb.aio_nbytes = BUFSIZE;
cb.aio_sigevent.sigev_notify = SIGEV_NONE;

while(1) {

/* copy one block asynchronously */
aioRet = aio_read(&cb);

if (aioRet == -1) {
fprintf(stderr, "%s", " aio_read failed:: ");
perror("");
exit(EXIT_FAILURE);
};
count++;
if(count == 5) break;

}

But when I tried to do this I'm getting an error message saying:
aio_read failed:: Invalid argument

I can't move on further in my program because of this read failure.
what's the reason for this?
I highly suspect it's because I'm trying to do aio_read in a while
loop. (when I remove the while loop it seem works) How do I fix this.
Do I have to use aio_suspend ? I tried that but it didn't resolve the
issue. may be I'm using it in a wrong way.

any help would be highly appreciated. Thanks in advance guys.

"danu" <> writes:
> I'm trying to read asynchronously from a file using aio_read:
[snip]

aio_read is not standard C. Try asking in a newsgroup that's specific
to your system.

--
Keith Thompson (The_Other_Keith) kst- <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

danu wrote:
> I'm trying to read asynchronously from a file using aio_read:

Good luck, aio_read is not part of the C standard so we don't know
anything about it.

>
> /* async I/O structures */
> struct aiocb cb;

Perhaps you should do:
struct aiocb cb = { 0 };
to ensure all fields are initialised.

<snip>

> /* copy one block asynchronously */
> aioRet = aio_read(&cb);
>

<snip>

> But when I tried to do this I'm getting an error message saying:
> aio_read failed:: Invalid argument

<snip>

> any help would be highly appreciated. Thanks in advance guys.

Try asking in a group dedicated to your system. There you might find
someone who knows about aio_read.
--
Flash Gordon
Still sigless on this computer.

On Mon, 31 Jul 2006 23:17:13 -0700, danu wrote:

> I'm trying to read asynchronously from a file using aio_read:
>
> /* async I/O structures */
> struct aiocb cb;
> const struct aiocb* list[1] = { &cb }; int aioRet;
>
> /* set appropriate values in control buffer */
> cb.aio_fildes = fromfd;
> cb.aio_buf = buffer0;
> cb.aio_nbytes = BUFSIZE;
> cb.aio_sigevent.sigev_notify = SIGEV_NONE;
>
> while(1) {
>
> /* copy one block asynchronously */
> aioRet = aio_read(&cb);
>
> if (aioRet == -1) {
> fprintf(stderr, "%s", " aio_read failed:: "); perror("");
> exit(EXIT_FAILURE);
> };
> count++;
> if(count == 5) break;
>
>
> }
> But when I tried to do this I'm getting an error message saying: aio_read
> failed:: Invalid argument
>
> I can't move on further in my program because of this read failure. what's
> the reason for this?
> I highly suspect it's because I'm trying to do aio_read in a while loop.
> (when I remove the while loop it seem works) How do I fix this. Do I have
> to use aio_suspend ? I tried that but it didn't resolve the issue. may be
> I'm using it in a wrong way.

It would indeed look like you're using aio_read improperly. Nothing you're
doing is asynchronous.

> any help would be highly appreciated. Thanks in advance guys.

Try comp.unix.programmer. The POSIX AIO interface is newish, so you might
have to exercise some patience.