Developer Guide and Reference

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Example for aio_error and aio_return Functions

The following example illustrates how the
aio_error()
and
aio_return()
functions can be used.
int aio_ex_3(HANDLE fd) {  static struct aiocb aio;  static struct aiocb *aio_list[] = {&aio};  int ret;  char *dat = "Hello from Ex-3\n";   /* Data initialization and asynchronously writing */    IC_AIO_DATA_INIT(aio, fd, dat, strlen(dat), 0);  if (aio_write(& aio) == -1) return errno;    ret = aio_error(&aio);  if ( ret == EINPROGRESS ) {  fprintf(stderr, "ERRNO=%d STR=%s\n", ret, strerror(ret));    ret = aio_suspend(aio_list, 1, NULL);  if (ret == -1) return errno;}  else if (ret)  return ret;    ret = aio_error(&aio);  if (ret) return ret;    ret = aio_return(&aio);  printf("ret=%d\n", ret);    return 0; }/* aio_ex_3 */
Result upon execution:
-bash-3.00$ ./a.out ERRNO=115 STR=Operation now in progress ret=16 -bash-3.00$ cat dat Hello from Ex-3
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);