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Top Forums Programming Please help:program hang stuck there signal handling on POSIX Message Queue UNIX C programming Post 302530712 by ouou on Tuesday 14th of June 2011 10:43:40 PM
Old 06-14-2011
Java help:wrong behavior code:client-server IPC signal handling on POSIX Message Queue UNIX C programming

in a single main() function,so need signal handling. Use Posix Message Queue IPC mechanism , can ignore the priority and other linked list message,to implement the scenario:

client:Knock Knock
server:who's there
client: Eric
Server:Eric,Welcome.
client:exit
all process terminated

stdin->POSIX MsgQ client send "knock knock" to server->Server compares string and send "who's there" back to client

Below is my code,

What I got is :
client:knock knock
Server:Who's there?
client:eric
eric
client:Exit
Exit


1st round succeed get the right result.From 2nd round, the client put the same typing on console.
Please help. Remember to use gcc -lrt to link mq_function.


Code:
#include <mqueue.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <string.h>
#define MSG_SIZE 100  //max size of msg
#define MAX_MSG 1  //max # of msg
#define FILE_MODE (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
static void sig_usr1(int signo) {
    mqflag = 1;
    sigprocmask(SIG_BLOCK, &newmask, &oldmask);
    return;
}


Last edited by ouou; 07-09-2011 at 09:00 PM.. Reason: How to get right indention when place code?
 

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Server::Client(3pm)					User Contributed Perl Documentation				       Server::Client(3pm)

NAME
Net::SMTP::Server::Client - Client session handling for Net::SMTP::Server. SYNOPSIS
use Carp; use Net::SMTP::Server; use Net::SMTP::Server::Client; use Net::SMTP::Server::Relay; $server = new Net::SMTP::Server('localhost', 25) || croak("Unable to handle client connection: $! "); while($conn = $server->accept()) { # We can perform all sorts of checks here for spammers, ACLs, # and other useful stuff to check on a connection. # Handle the client's connection and spawn off a new parser. # This can/should be a fork() or a new thread, # but for simplicity... my $client = new Net::SMTP::Server::Client($conn) || croak("Unable to handle client connection: $! "); # Process the client. This command will block until # the connecting client completes the SMTP transaction. $client->process || next; # In this simple server, we're just relaying everything # to a server. If a real server were implemented, you # could save email to a file, or perform various other # actions on it here. my $relay = new Net::SMTP::Server::Relay($client->{FROM}, $client->{TO}, $client->{MSG}); } DESCRIPTION
The Net::SMTP::Server::Client module implements all the session handling required for a Net::SMTP::Server::Client connection. The above example demonstrates how to use Net::SMTP::Server::Client with Net::SMTP::Server to handle SMTP connections. $client = new Net::SMTP::Server::Client($conn) Net::SMTP::Server::Client accepts one argument that must be a handle to a connection that will be used for communication. Once you have a new client session, simply call: $client->process This processes an SMTP transaction. THIS MAY APPEAR TO HANG -- ESPECIALLY IF THERE IS A LARGE AMOUNT OF DATA BEING SENT. Once this method returns, the server will have processed an entire SMTP transaction, and is ready to continue. Once $client->process returns, various fields have been filled in. Those are: $client->{TO} -- This is an array containing the intended recipients for this message. There may be multiple recipients for any given message. $client->{FROM} -- This is the sender of the given message. $client->{MSG} -- The actual message data. :) AUTHOR AND COPYRIGHT Net::SMTP::Server / SMTP::Server is Copyright(C) 1999, MacGyver (aka Habeeb J. Dihu) <macgyver@tos.net>. ALL RIGHTS RESERVED. You may distribute this package under the terms of either the GNU General Public License or the Artistic License, as specified in the Perl README file. SEE ALSO
Net::SMTP::Server::Server, Net::SMTP::Server::Relay perl v5.10.1 1999-12-28 Server::Client(3pm)
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