Re: [Boost-users] ASIO ssl::stream read/write_some question.

From: Eugene M. Kim (gene_at_[hidden])
Date: 2008-02-26 20:20:24

Derrick Hathaway wrote:
> Could someone please shed some light on ASIO SSL reads and writes for 
> me? The names of the read and write functions for the ssl::stream 
> (read_some and write_some) imply to me that the buffer(s) may not be 
> completely filled/sent with a read/write. Do I need to have some 
> intermediate handler that will begin another async_read/write_some 
> until my buffer is filled/flushed? The documentation doesn't seem to 
> indicate that this is necessary. It makes sense from the example that 
> the reads may not fill the provided buffer before invoking the 
> handler. So it may be necessary to call read_some multiple times until 
> the expected number of bytes is received. But is this also the case 
> with writes, and if so, how do I manage multiple writes if I provide a 
> vector of buffers to be written with and async_write_some?
I have no authority to give a definite answer, but my experience with it 
indicates that what you assume is indeed right.  All 
read_some/write_some methods may read or write fewer bytes than 
requested, and you need to check the num_transferred placeholder and 
invoke read_some/write_some again as necessary.

I remember seeing an adapter method that does this for you in some other 
class, but I forgot exactly where it is (didn't need/want to use it in 
my program).

Cheers,
Eugene