RE: Socket bug???

Gerald,

On Mon, 26 Jan 2004 GKern@xxxxxxxxxxxxxxxx wrote:
>  * Send the segment to the server over the socket...
>  * (NOTE - Need to add 2 to SockDtaLen since SocketData is defined as
>  *  VARYING - which adds 2 extra bytes to the field since the first
>  *  two bytes contain a binary value that identifies the actual length
>  *  of the data in the variable length field...)
> C                   Eval      RC = Write(SD:%Addr(SocketData):SockDtaLen+2)

I don't know if this is intentional, but your code is sending not only the
data in the "SocketData" string, but also the 2 bytes at the start which
indicate the length of the string.

If the receiving program isn't expecting to receive that 2-byte length, it
may be confused about how to handle this.  If the length happens to be 11,
for example, you'd get two bytes x'00' and x'0b' as the first two bytes of
the data that is sent.

What you probably want to do is code it like this:

> C      Eval      RC = Write(SD:%Addr(SocketData)+2:SockDtaLen)

That way, it will only send the string, not the length that precedes it.

also, unless you're coding blocking sockets (which is a nice place to
start learning, but makes for a less robust application) you'll want to do
this sending in a loop, keep adding the length already sent to the address
and subtracting it from "SockDtaLen".

RC doesn't just tell you if it succeeded or failed, it also tells you how
much of your data got sent.

Hope that helps...