C Programming: Anyone know how to use socket select() function?
hello socket programming expert,
I having difficulties in understanding how select() function in socket programming work.... I'm trying to create my own peer-to-peer chat or file transfer program by using the select() function.... Therefore does anyone had any tutorial or source code that related to either one of the program, which I'm trying to create?
My problem is how to get the "write" in select() function working?
Let say:
and now, how do I get the server side to print the word "Server is writing......." ? I hope you guy understand what I mean.......
btw, I'm using NetBDS and using C programming....... hoping someone can help me out :-D
Hi All,
I encountered a stange problem while doing a perl script to use socket. i need to transfer a file from client to sever. but error came as argument missing in send function.........Plz tell me the wt r the arguments in send and recv functions....... (0 Replies)
I have a socket and a message queue over which i am trying to multiplex input using select().
When data comes over socket the select works but when it comes over message queue the select is not detecting it .
Create_Q gets the identifier of the messege queue.
... (1 Reply)
Hello All,
I have a problem using connect(...) function in C++. I am using SSH from my windows system to connect it to linux server. The program works fine if I run it directly in Linux machine but I need it to run through windows machine.
The function returns -1 and so my program terminates.
... (3 Replies)
Hi,
I have a client-server socket program. It has been working fine for over a year, but recently it started to show strange behavior.:confused:
After the server program runs for a while, it will show in the top command saying it is using lots of CPU, MEM. I assume it means the server code is... (1 Reply)
Hi,
I was porting ipv4 application to ipv6; i was done with TCP transports. Now i am facing problem with SCTp transport at runtime.
To test SCTP transport I am using following server and client socket programs. Server program runs fine, but client program fails giving Invalid Arguments for... (0 Replies)
Why does this socket function only read the first 1440 chars of the stream. Why not the whole stream ? I checked it with gdm and valgrind and everything seems correct...
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include... (3 Replies)
Hi, I am a newbie about network programming. All codes come from this book: UNIX Network Programming Volume 1, Third Edition.
It is a TCP server by use select()
int main(int argc, char **argv) {
int i, maxi, maxfd, listenfd, connfd, sockfd;
int ... (2 Replies)
I have created two sockets and binded both. My requirement is that 2nd socket must send/ recv data only on expiration of timeval(tv). but the 1st socket must keep on send/recv the data without waiting for the 2nd socket completion......
I have posted my code below......
In this code the 2nd... (3 Replies)
Discussion started by: naresh046
3 Replies
LEARN ABOUT MOJAVE
net::server::sig
Net::Server::SIG(3) User Contributed Perl Documentation Net::Server::SIG(3)NAME
Net::Server::SIG - adpf - Safer signal handling
SYNOPSIS
use Net::Server::SIG qw(register_sig check_sigs);
use IO::Select ();
use POSIX qw(WNOHANG);
my $select = IO::Select->new();
register_sig(PIPE => 'IGNORE',
HUP => 'DEFAULT',
USR1 => sub { print "I got a SIG $_[0]
"; },
USR2 => sub { print "I got a SIG $_[0]
"; },
CHLD => sub { 1 while waitpid(-1, WNOHANG) > 0; },
);
# add some handles to the select
$select->add(*STDIN);
# loop forever trying to stay alive
while(1) {
# do a timeout to see if any signals got passed us
# while we were processing another signal
my @fh = $select->can_read(10);
my $key;
my $val;
# this is the handler for safe (fine under unsafe also)
if (check_sigs()) {
# or my @sigs = check_sigs();
next unless @fh;
}
my $handle = $fh[@fh];
# do something with the handle
}
DESCRIPTION
Signals prior in Perl prior to 5.7 were unsafe. Since then signals have been implemented in a more safe algorithm. Net::Server::SIG
provides backwards compatibility, while still working reliably with newer releases.
Using a property of the select() function, Net::Server::SIG attempts to fix the unsafe problem. If a process is blocking on select() any
signal will short circuit the select. Using this concept, Net::Server::SIG does the least work possible (changing one bit from 0 to 1).
And depends upon the actual processing of the signals to take place immediately after the the select call via the "check_sigs" function.
See the example shown above and also see the sigtest.pl script located in the examples directory of this distribution.
FUNCTIONS
"register_sig($SIG => &code_ref)"
Takes key/value pairs where the key is the signal name, and the argument is either a code ref, or the words 'DEFAULT' or 'IGNORE'. The
function register_sig must be used in conjunction with check_sigs, and with a blocking select() function call -- otherwise, you will
observe the registered signal mysteriously vanish.
"unregister_sig($SIG)"
Takes the name of a signal as an argument. Calls register_sig with a this signal name and 'DEFAULT' as arguments (same as
register_sig(SIG,'DEFAULT')
"check_sigs()"
Checks to see if any registered signals have occured. If so, it will play the registered code ref for that signal. Return value is
array containing any SIGNAL names that had occured.
"sig_is_registered($SIG)"
Takes a signal name and returns any registered code_ref for that signal.
AUTHORS
Paul Seamons (paul@seamons.com)
Rob B Brown (rob@roobik.com) - Provided a sounding board and feedback in creating Net::Server::SIG and sigtest.pl.
LICENSE
This package may be distributed under the terms of either the
GNU General Public License
or the
Perl Artistic License
All rights reserved.
perl v5.18.2 2013-01-09 Net::Server::SIG(3)