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
16
Other forums
Struct/union and scope problem!
HI all , I have
Code:
in header.h
typedef struct Node Link;
/* ---------
Inserting multiple records from single form
I've found a number of threads that deal with this issue, but I'm new to php and coding language so
LinkedList help
Ok so I just learned quickly about lists, so I have a not too hard project I think, but am having a
Clean URLs
Hi I was wandering if anyone has ever implemented URLs on their PHP run website using URLS like wiki
Update not working ... please help
Hi,
I am trying to update a row using an edit form by passing id of the row .. but it is not
Lack of simpleXML Documentation
What is up with this.
Look at: http://www.php.net/manual/en/function.simplexml-load-file.php<
links using header()
Hi All
I'm not sure where to ask for help on this but I hope someone can offer some. I'm at
Problem with Subscreen
Dear Experts ,
I am facing a problem with the subscreens. My senario is as follows :
query based on 2 conditions
I want to select if the doc_type is either s OR f but this doesn't work:
Code: [Select]$query
Sort a two dimensional array.
Hi. I've set up a two dimensional array that reads as follows:
Code: $modifiedData = array(