A stream handle service must meet the requirements for a handle
service, as well as the additional requirements listed below.
In the table below, X denotes
a stream handle service class, a
denotes a value of type X,
b denotes a value of type
X::implementation_type, ec
denotes a value of type error_code,
mb denotes a value satisfying
mutable buffer
sequence requirements, rh
denotes a value meeting ReadHandler requirements, cb denotes a value satisfying constant
buffer sequence requirements, and wh
denotes a value meeting WriteHandler requirements.
Table 29. StreamHandleService requirements
|
expression
|
return type
|
assertion/note
pre/post-condition
|
|
a.read_some(b, mb, ec);
|
size_t
|
pre: a.is_open(b).
Reads one or more bytes of data from a handle b.
The mutable buffer
sequence mb specifies
memory where the data should be placed. The operation shall always
fill a buffer in the sequence completely before proceeding to the next.
If successful, returns the number of bytes read. Otherwise returns
0. If the total size of
all buffers in the sequence mb
is 0, the function shall
return 0 immediately.
If the operation completes due to graceful connection closure
by the peer, the operation shall fail with error::eof.
|
|
a.async_read_some(b, mb, rh);
|
void
|
pre: a.is_open(b).
Initiates an asynchronous operation to read one or more bytes
of data from a handle b.
The operation is performed via the io_service
object a.io_service()
and behaves according to asynchronous
operation requirements.
The mutable buffer sequence
mb specifies memory
where the data should be placed. The operation shall always fill a
buffer in the sequence completely before proceeding to the next.
The implementation shall maintain one or more copies of mb until such time as the read operation
no longer requires access to the memory specified by the buffers in
the sequence. The program must ensure the memory is valid until:
— the last copy of mb
is destroyed, or
— the handler for the asynchronous operation
is invoked,
whichever comes first. If the total size of
all buffers in the sequence mb
is 0, the asynchronous
read operation shall complete immediately and pass 0
as the argument to the handler that specifies the number of bytes read.
If the operation completes due to graceful connection closure
by the peer, the operation shall fail with error::eof.
If the operation completes successfully, the ReadHandler
object rh is invoked
with the number of bytes transferred. Otherwise it is invoked with
0.
|
|
a.write_some(b, cb, ec);
|
size_t
|
pre: a.is_open(b).
Writes one or more bytes of data to a handle b.
The constant buffer sequence cb
specifies memory where the data to be written is located. The operation
shall always write a buffer in the sequence completely before proceeding
to the next.
If successful, returns the number of bytes
written. Otherwise returns 0.
If the total size of all buffers in the sequence cb
is 0, the function shall
return 0 immediately.
|
|
a.async_write_some(b, cb, wh);
|
void
|
pre: a.is_open(b).
Initiates an asynchronous operation to write one or more bytes
of data to a handle b.
The operation is performed via the io_service
object a.io_service()
and behaves according to asynchronous
operation requirements.
The constant buffer sequence
cb specifies memory
where the data to be written is located. The operation shall always
write a buffer in the sequence completely before proceeding to the
next.
The implementation shall maintain one or more copies
of cb until such time
as the write operation no longer requires access to the memory specified
by the buffers in the sequence. The program must ensure the memory
is valid until:
— the last copy of cb
is destroyed, or
— the handler for the asynchronous operation
is invoked,
whichever comes first. If the total size of
all buffers in the sequence cb
is 0, the asynchronous
operation shall complete immediately and pass 0
as the argument to the handler that specifies the number of bytes read.
If the operation completes successfully, the WriteHandler
object wh is invoked
with the number of bytes transferred. Otherwise it is invoked with
0.
|
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