.\" static inline void io_prep_pread(struct iocb *iocb, int fd, void *buf, size_t count, long long offset)
.\" {
.\" 	memset(iocb, 0, sizeof(*iocb));
.\" 	iocb->aio_fildes = fd;
.\" 	iocb->aio_lio_opcode = IO_CMD_PREAD;
.\" 	iocb->aio_reqprio = 0;
.\" 	iocb->u.c.buf = buf;
.\" 	iocb->u.c.nbytes = count;
.\" 	iocb->u.c.offset = offset;
.\" }
.TH io_prep_pread 3 2009-06-10 "Linux 2.4" Linux AIO"
.SH NAME
io_prep_pread \- Set up asynchronous read
.SH SYNOPSYS
.nf
.B #include <errno.h>
.sp
.br
.B #include <libaio.h>
.br
.sp
.BI "inline void io_prep_pread(struct iocb *" iocb ", int " fd ", void *" buf ", size_t " count ", long long " offset ");"
"
.sp
struct iocb {
	void		*data;
	unsigned	key;
	short		aio_lio_opcode;
	short		aio_reqprio;
	int		aio_fildes;
};
.fi
.SH DESCRIPTION
.B io_prep_pread
is an inline convenience function designed to facilitate the initialization of
the iocb for an asynchronous read operation.

The first
.IR "iocb->u.c.nbytes = count"
bytes of the file for which
.IR "iocb->aio_fildes = fd"
is a descriptor are written to the buffer
starting at
.IR "iocb->u.c.buf = buf" .
Reading starts at the absolute position
.IR "ioc->u.c.offset = offset"
in the file.
.PP
This function returns immediately. To schedule the operation, the
function 
.B io_submit
must be called.
.PP
Simultaneous asynchronous operations using the same \fIiocb\fP produce
undefined results.
.SH "RETURN VALUES"
None.
.SH ERRORS
None.
.SH "SEE ALSO"
.BR io (3),
.BR io_cancel (3),
.BR io_fsync (3),
.BR io_getevents (3),
.BR io_prep_fsync (3),
.BR io_prep_pwrite (3),
.BR io_queue_init (3),
.BR io_queue_release (3),
.BR io_queue_run (3),
.BR io_queue_wait (3),
.BR io_set_callback (3),
.BR io_submit (3),
.BR errno (3).