Example for lio_listio Function

The following example illustrates how the lio_listio() function can be used.

int aio_ex_5(HANDLE fd)

{

  static struct aiocb   aio[2];

  static struct aiocb  *aio_list[2] = {&aio[0], &aio[1]};

   int               i, ret;

/*

 ** Data initialization and Synchronously writing

*/

 IC_AIO_DATA_INIT(aio[0], fd, "rec#1\n", strlen("rec#1\n"), 0)

 IC_AIO_DATA_INIT(aio[1], fd, "rec#2\n", strlen("rec#2\n"),

 aio[0].aio_nbytes)

 aio[0].aio_lio_opcode = aio[1].aio_lio_opcode = LIO_WRITE;

 ret = lio_listio(LIO_WAIT, aio_list, 2, 0);

 if (ret) return ret;

 return 0;

}/* aio_ex_5 */

Result upon execution:

-bash-3.00$ ./a.out

-bash-3.00$ cat dat

rec#1

rec#2

-bash-3.00$

Remarks:

1. In the example, the IC_AIO_DATA_INIT is defined as follows:

   #define IC_AIO_DATA_INIT(_aio, _fd, _dat, _len, _off)\

     {memset(&_aio, 0, sizeof(_aio)); \

      _aio.aio_fildes = _fd;          \

      _aio.aio_buf    = _dat;         \

      _aio.aio_nbytes = _len;         \

      _aio.aio_offset = _off;}

2. The file descriptor fd is obtained as:

   HANDLE fd = CreateFile("dat",

      GENERIC_READ | GENERIC_WRITE,

      FILE_SHARE_READ,

      NULL,

      OPEN_ALWAYS,

      FILE_ATTRIBUTE_NORMAL/*|FILE_FLAG_OVERLAPPED*/,

      NULL);

3. The aio_lio_opcode refers to the field of each aiocb structure that specifies the operation to be performed. The supported operations are LIO_READ (do a 'read' operation), LIO_WRITE (do a 'write' operation), and LIO_NOP (do no operation); these symbols are defined in <aio.h>.