Question

I work on an C++ project in Linux where two programs communicate over a named pipe.

Now I want to detect in one program if the other disconnects from the named pipe.

Is there a way to detect the disconnect?

Edit

I opened the fifo in O_RDWR mode – that was the reason that select didn’t react on the disconnect. Now I open the fifo with (O_RDONLY | O_NDELAY) and all works fine.

Answer 1

This is same as in TCP/IP. You need to attempt to read data, if that fails with 0, pipe is closed.

read and recv:

These calls return the number of bytes received, or -1 if an error
occurred. The return value will be 0 when the peer has performed an
orderly shutdown.

There is also SIGPIPE signal. It’ll be sent when you try write to a broken pipe – pipe with no readers.