Re: Using GNAT.Sockets

[Michael Paus <pausnospam@nospamib-paus.com>]

Bob Spooner wrote:

> Well, it's not _quite_ that simple...
> "Michael Paus" <pausnospam@nospamib-paus.com> wrote in message
> news:d3o9le$cgm$1@online.de...
> 
>>markp wrote:
>>
>>
>>>Bob,
>>>
>>>Thanks for your reply. My basic quesion is I realize that a socket read
>>>will not necessarily return all the data requested. The Receive_Socket
>>>item input parameter takes and array. Will a subsequent read place data
>>>at the beginning of the array, meaning I have to copy data out before I
>>>read again?
>>
>>Yes it does but you do not have to copy your data. Just have a look at
>>Duncans example. He told you already how to do it. You just have to call
>>this in a loop until Last = My_Buffer'Last.
>>
>>   procedure Receive_Socket
>>     (Socket => My_Socket,
>>      Item   => My_Buffer (Last + 1 .. My_Buffer'Last),
>>      Last   => Last);
>>
>>The first byte will be stored at the first position of the buffer array
>>you provide, but in the above example we specify a sub-range of the
>>whole buffer and so the first element of this is at the index Last + 1
>>of the whole buffer and this is exactly what you need.
>>
>>Michael
> 
> 
> Your buffer needs to be big enough to read the largest message you expect,
> and for the shorter messages, you need to use a slice of the buffer equal to
> the size of the message being read so that you don't read in some of the
> following message along with the current message.

Yes, of course the assumption in the above example is that your intention
is to finally read exactly My_Buffer'Length bytes.

Michael