/*
* New collapsed (a)synchronous interface.
*
* If the IO is asynchronous (i.e. it has notify.fn), you must either unplug
* the queue with blk_unplug() some time later or set REQ_SYNC in
io_req->bi_rw. If you fail to do one of these, the IO will be submitted to
* the disk after q->unplug_delay, which defaults to 3ms in blk-settings.c.
*/
int dm_io(struct dm_io_request *io_req, unsigned num_regions,
struct dm_io_region *where, unsigned long *sync_error_bits)
{
int r;
struct dpages dp;
r = dp_init(io_req, &dp);
if (r)
return r;
if (!io_req->notify.fn)
return sync_io(io_req->client, num_regions, where,
io_req->bi_rw, &dp, sync_error_bits);
return async_io(io_req->client, num_regions, where, io_req->bi_rw,
&dp, io_req->notify.fn, io_req->notify.context);
}
int hpx_main()
{
{
// Initiate an asynchronous IO operation wait for it to complete without
// blocking any of the HPX thread-manager threads.
hpx::lcos::future<int> f = async_io("Write this string to std::cout");
// This will suspend the current HPX thread until the IO operation is
// finished.
int result = f.get();
// Print the returned result.
hpx::cout << "HPX-thread: The asynchronous IO operation returned: "
<< result << "\n" << hpx::flush;
}
return hpx::finalize(); // Initiate shutdown of the runtime system.
}
static int async_write(struct async *as)
{
return async_io(as, 0 /* No read. */);
}
static int async_read_write(struct async *as)
{
return async_io(as, 1 /* Read too. */);
}
