QNX Operating System/Discussion/OSTech/UDP sockets can not be disconnected on QNX. AF_UNSPEC not supported./List of Posts
 
Forum Topic - UDP sockets can not be disconnected on QNX. AF_UNSPEC not supported.: (6 Items)
   
Update
Stefan Holzmüller
11/02/2015 10:03 AM
post114862
UDP sockets can not be disconnected on QNX. AF_UNSPEC not supported.   

The attached program when compiled and linked for qnx6.5  


$ ./tmp/UDP  10.131.1.141 
before connect 
Local binding: address=10.131.1.141, port=65426
before disconnect 
connect failed: Address family not supported by protocol family
Local binding: address=0.0.0.0, port=65426
before disconnect -2222222222222222
Local binding: address=10.131.1.141, port=65426
bind again 
Local binding: address=10.131.1.141, port=65426

while this runs fine on Linux. 


Can you please let me know if its possible to disconnect from a UDP socket on qnx6.5 ?
Attachment: Text UDPSocket_linux.c 2.26 KB
Gervais Mulongoy
11/02/2015 10:17 AM
post114864
RE: UDP sockets can not be disconnected on QNX. AF_UNSPEC not supported.   
If you ignore the error message have you validated that the socket was "disconnected"?
Stefan Holzmüller
11/03/2015 9:33 AM
post114870
Re: RE: UDP sockets can not be disconnected on QNX. AF_UNSPEC not supported.   
Gravis, 

Your help is appreciated.. It works in actuality.. Do you know why this error is reported in this case? i dont assume 
that this is how it was designed to work. is it?
Stefan Holzmüller
11/03/2015 9:54 AM
post114871
Re: RE: UDP sockets can not be disconnected on QNX. AF_UNSPEC not supported.   
i meant Gervais.. I am sorry for the typo on the name.. sincere apologies.
Gervais Mulongoy
11/03/2015 10:23 AM
post114872
RE: RE: UDP sockets can not be disconnected on QNX. AF_UNSPEC not supported.   
Hello Stefan,

I am not sure why the error is reported, but based on the output of your test program it looked like it changed 
something hence why I figured let's check to see if the connection was "disconnected".

I would imagine that different OSes behave differently, some might report an error others might not.

Gervais
Alexey Bakhtin(deleted)
03/21/2018 5:47 AM
post118687
Re: UDP sockets can not be disconnected on QNX. AF_UNSPEC not supported.   
I've struggled with the same issue on QNX v7.0 armle
My program creates DGRAM socket and connects to specific address/port. During connection DGRAM socket automatically 
bounds to the local address. After that I have to disconnect DGRAM socket and continue send/receive packets without 
connection to remote host.
According to documentation of connect function (http://www.qnx.com/developers/docs/7.0.0/index.html#com.qnx.doc.neutrino
.lib_ref/topic/c/connect.html): "Datagram sockets may dissolve the association by connecting to an invalid address, such
 as a null address". Unfortunately It seems does not work:
1) connect(fd, NULL, 0) 
    returns EFAULT and UDP connection remains connected to remote host/port
2) memset(&addr, 0, addr_len);
    connect(fd, (struct sockaddr *)&addr, addr_len)
    returns EAFNOSUPPORT but DGRAM connection successfully disconnected from the remote host. However this operation 
breaks binding of DGRAM socket to local address:
    getsockname(fd, (struct sockaddr *)&addr, &addr_len) always returns 0.0.0.0 address. Any subsequent calls to bind(fd
, struct sockaddr *)&local_addr, addr_len) fails with EINVAL. So, no way to fix binding to the correct local host 
address.

What is the correct way to disconnect UDP socket without side effects ?

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