HP-UX Reference (11i v1 00/12) - 2 System Calls (vol 5)

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aio_read(2) aio_read(2)

[EEXIST] The aiocbp is already in use for another asynchronous I/O operation.

Once the read request has been enqueued by aio_read(), the following errors, in addition to all of the

errors normally reported by the read() function, may be reported asynchronously by a subsequent call to

aio_error() or aio_return() referencing its aiocb.

[EBADF] The aiocbp->aio_fildes was not a valid ﬁle descriptor open for reading.

[EINVAL] The value of aiocbp->aio_reqprio is not valid.

[EINVAL] The value of aiocbp->aio_nbytes is invalid.

[EINVAL] The ﬁle offset implied by aiocbp->aio_offset or aiocbp-

>aio_offset

+aiocbp->aio_nbytes are not valid for the ﬁle at the time the

request is processed.

[ECANCELED]

The read operation was canceled due to a subsequentcall to aio_cancel() .

EXAMPLE

The following code sequence and call to aio_read()

starts an asynchronous read operation.

#include <fcntl.h>

#include <errno.h>

#include <aio.h>

char buf[4096];

ssize_t retval; ssize_t nbytes;

struct aiocb myaiocb;

bzero( &myaiocb, sizeof (struct aiocb));

myaiocb.aio_fildes = open( "/dev/null", O_RDONLY);

myaiocb.aio_offset = 0;

myaiocb.aio_buf = (void *) buf;

myaiocb.aio_nbytes = sizeof (buf);

myaiocb.aio_sigevent.sigev_notify = SIGEV_NONE;

retval = aio_read( &myaiocb );

if (retval) perror("aio_read:");

/* continue processing */

...

/* wait for completion */

while ( (retval = aio_error( &myaiocb) ) == EINPROGRESS) ;

/* free the aiocb */

nbytes = aio_return( &myaiocb);