io_prep_pread (3)

Leading comments

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;
}

(The comments found at the beginning of the groff file "man3/io_prep_pread.3".)

NAME

io_prep_pread - Set up asynchronous read

SYNOPSIS

#include <errno.h>



#include <libaio.h>


inline void io_prep_pread(struct iocb *iocb, int fd, void *buf, size_t count, long long offset);
"

struct iocb {
        void            *data;
        unsigned        key;
        short           aio_lio_opcode;
        short           aio_reqprio;
        int             aio_fildes;
};

DESCRIPTION

io_prep_pread is an inline convenience function designed to facilitate the initialization of the iocb for an asynchronous read operation.
The first iocb->u.c.nbytes = count bytes of the file for which iocb->aio_fildes = fd is a descriptor are written to the buffer starting at iocb->u.c.buf = buf. Reading starts at the absolute position ioc->u.c.offset = offset in the file.

This function returns immediately. To schedule the operation, the function io_submit must be called.

Simultaneous asynchronous operations using the same iocb produce undefined results.

RETURN VALUES

None.

ERRORS

None.

SEE ALSO

io(3), io_cancel(3), io_fsync(3), io_getevents(3), io_prep_fsync(3), io_prep_pwrite(3), io_queue_init(3), io_queue_release(3), io_queue_run(3), io_queue_wait(3), io_set_callback(3), io_submit(3), errno(3).