problem running a UDP client and server

Corinna Vinschen
Mon Jun 26 12:24:00 GMT 2006

On Jun 26 17:41, Varun Sharma wrote:
> Hi,
>  I have been trying to run the abing code
> ( It basically set up a
> UDP client and server and then there are excahnge of UDP packets. I have
> been running into troubles since when I have been trying to install it.
>  Firstly the make file had the -lnsl option which it cannot find in
> cygwin, so I removed it and compiled the code and everything worked fine
> with the warning that it cannot find the -pthread option.
>  Then to run the reflector in abing, one has to execute the following
> commmand.
> ./abw_rfl -c &
> ./abing -c
> ./abw_rfl &
> But in my case, I get an error when I run ./abing -c saying that revcfrom
> failed with invalid argument. The code works fine with no error at all in
> a normal linux distro. I am unable to find out the difference. Even UDP
> clients and server codes which can be easily downloaded from the net work
> fine.
>  I would be really obliged if someone can tell me the problem or some
> ekind of an experience he or she has on installing and using abing on
> cygwin.

This would require to get some more details from you besides "recvfrom
returns EINVAL".

Anyway, I have a wild guess.  Windows' recvfrom only understands MSG_OOB
and MSG_PEEK.  Any other flag value is unsupported and should result in
recvfrom returning EINVAL.  Maybe that's your problem.  Solution:  Don't
use flags except MSG_OOB and MSG_PEEK.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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