Unix domain sockets

svm · 11-22-2010, 04:57 PM

Hello,

I am new to the forum, please correct me if I am posting in the wrong forum..

While using UNIX domain sockets for IPC between two processes, the "Resource temporarily unavailable" error is thrown constantly. What are the possible options to fix the issue?

I have increased the receive buffer size at /proc/sys/net/unix/max_dgram_qlen . What other socket buffer sizes, relevant to unix domain sockets can result in this error??

Any inputs on the common problems that result in this error will be very helpful.

Thank you,
Vidya

paulsm4 · 11-22-2010, 05:12 PM

It sounds like you're using non-blocking I/O

Check out these resources:

Quote:

http://developerweb.net/viewtopic.php?id=5792

"Resource temporarily unavailable" is EAGAIN, aka EWOULDBLOCK... You will get it only on file descriptors that you have explicitly set to non-blocking I/O mode... And, it indicates that your I/O operation would normally have blocked at that point, because it couldn't occur immediately... (Ie: for reading, there's currently no data to read; for writing, the buffer is full and needs to be emptied first...)

Beej's Guide to Network Programming

Problems with FIFO pipe using a child and parent process

'Hope that helps!

svm · 11-22-2010, 07:33 PM

Hi Paul,

Thank you very much for the links. Yes, that is exactly what I am trying to do - non-blocking I/O. As my processes are interrupted by signals, frequently, I have to receive, send in non-blocking mode. (The other option is to use select but even select is interrupted by signals!) So, I get the error during send/write, because the buffer(send/receive) is full. Other than, reducing the frequency of my IPC messages, I wanted to know what are the socket buffer sizes I could increase, that can possibly resolve the issue?

Thank you,
Vidya