can i connect to the network?

os2 · 02-09-2005, 10:31 AM

hi

i develop a program (c language) with linux.
every x second, i send some data to a server...
if the connection to the server fail, i would like to save to the local machine...

my solution:

i do a nfs link, /opt/good exist only on the server
my code:

Code:

exist = stat ( "/opt/good",&buf );
if(exist==0)
  printf("network on\n");
else
  printf("network off\n");

surely if the connection to the network fail, the program can stop...

what is the best way to do that?

thanks

Frustin · 02-09-2005, 10:46 AM

why dont you have the program "ping" the nfs?

os2 · 02-09-2005, 11:13 AM

that can work... but it's surely not the better solution

i can't imagine that: konqueror, kopete, icq, msn client... do a ping to know if they are a network problem...

what is the best solution?

chrism01 · 02-10-2005, 12:17 AM

If you use TCP, you should get an error returned if the remote server does not respond/ack your pkts.

Tinkster · 02-10-2005, 12:59 AM

Quote:

Originally posted by os2
every x second, i send some data to a server...

What exactly are you doing there?
Writing bytes to a socket, fprint to an nfs share?

Cheers,
Tink

Frustin · 02-10-2005, 01:23 AM

wouldnt it return a standard error if it didnt get written? therefore you just need to look for the std error. if you are writing that frequently then a: does it matter if it misses the odd write? and b: (as an after thought) save the unwritten bits to a file and try to resend after connection (i.e. you dont get error anymore) has been re-estabilished.

os2 · 02-10-2005, 08:40 AM

Quote:

Originally posted by Tinkster
What exactly are you doing there?
Writing bytes to a socket, fprint to an nfs share?

Cheers,
Tink

ya, i do fprintf to an nfs share

Tinkster · 02-10-2005, 11:38 AM

That's a (if the network connection isn't too stable) rather
unreliable method, then, either way your program will
have at least the wait of the NFS timeout (3 minutes on
my machines) before it returns its -1 or the write fails ...

I'd go with the ping method....

Cheers,
Tink

Frustin · 02-11-2005, 01:05 AM

me too.