Web Server Flow Control

[Richard Falt]

Dear Forum,
We have a web server application that is ported to numerous Unix flavors but the flow control does not work on HP-UX 11i.

Before we get ready to do a send() on the socket we do a setsockopt SO_SNDLOWAT to 4096.

Then we do a poll() on the other Unix flavors poll() will only give "Clear to Send" if there is 4097 Bytes available in the buffer whereas HP-UX will give clear to send if there is 1 byte in the buffer.

We have found out that HP-UX does not support SO_SNDLOWAT and that this is the expected behaviour of poll().

How are we supposed to do a check if there is sufficient buffer space before we do the send().

Any ideas appreciated,

Richard F??lt