UDP server recvfrom() always returns -1? :(


Posted on 16th Feb 2014 07:03 pm by admin

Hello all,
I am getting a very strange error in my code :( I am writing a server application in C, to send and receive UDP packets to/from a client. Right now, im just running a loop in which the server receives packets using recvfrom() however.... the function seems to block and everytime I send it something, it sets errno to "resource temporarily unavailable" which is strange, cause it blocks until I send something, meaning that it knows something came no? However, recvfrom always returns -1 This is how I initialized the socket:

//struct timeval tv;

if((s = socket(AF_INET, SOCK_DGRAM, 0))==-1)
return 0;

bzero(&si_me,sizeof(si_me));
si_me.sin_family = AF_INET;
si_me.sin_port = htons(PORT);
si_me.sin_addr.s_addr = htonl(INADDR_ANY);

/*** Set socket timeout ***
tv.tv_sec = 1;
tv.tv_usec = 0;
if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0)
{
printf("Couldn't set socket timeoutn");
return 0;
}*/

if(bind(s,(struct sockaddr*) &si_me, sizeof(si_me))==-1)
return 0;

return 1;

and then I ran:
do
{
done = recvData();
printf("Received %d n", done);

}while(done == 0);

with recvData() being:

int recvData(void)
{
if (recvfrom(s, (char*)&buf, UDP_BUFFER_LEN, 0, (struct sockaddr*) &si_other_comp, &slen)==-1)
{
printf("Couldn't read socket (%s)n",strerror(errno));
return 0;
}

return 1;
}

so, program does nothing until it gets a packet, then says it cant read it and then continues doing nothing until it gets another packet.... any ideas?

No comments posted yet

Your Answer:

Login to answer
125 Like 16 Dislike
Previous forums Next forums
Other forums

Hit counter updating once per IP - IP HIT COUNTER
I have a hit counter, for the amount of views on a tutorial.
It'll do the query and then do..

Got A Free Server :(
So I was given a free server

http://shopping.yahoo.com/p:Compaq%20ProLiant%201500%20Server:1

Displaying Site Logo/Icon on a Title tag
really need some help out here. I want to insert a Logo/Icon just like the one close to the "PH

preg-match with a string and numbers
Hi, I can't get the expression to work for my preg_match, what I'd like is for it to match the strin

registration form
first time posting. did some searches but didnt find exactly what i am looking for. dont flame cause

php form help
Hey,

I use a control file to set my meta tags and titles

Here's an example
Code: &a

Please Help my PHP Dating Function.
Hi everyone!

Well here is my code that displays this:

It works wonderful.


Date help - fetch dates for Mondays between xxx and yyy?
Does anyone know the best way to do this? I have two dates, say:

2010-01-26 and 2010-05-30

Java API in PHP?
I have an application that we use internally here at the office.

The software company provide

php require help needed
Ok i tried to use the search funtion but the word require is everywhere.

i'm really new to cr

Sign up to write
Sign up now if you have flare of writing..
Login   |   Register
Follow Us
Indyaspeak @ Facebook Indyaspeak @ Twitter Indyaspeak @ Pinterest RSS



Play Free Quiz and Win Cash