*What is likely happening is that you have the first message queued by the OS before there is a notification that the remote end was down and only on the second send do you see the error.
when i send msgs before the pipe is broked, the OS sends them immediately , then y is it queuing the 1st msg when the socket is broken??
See if u can find a way around this..
the client and server code is ..
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <memory.h>
#include <errno.h>
#include <signal.h>
using namespace std;
int MAXLEN=1024;
int PORT=20000;
void sigHlr(int sigNo)
{
cout << "SIGNAL Received " << sigNo;
}
main( int argc, char *argv[])
{
struct sockaddr_in serv;
int sockfd,newsockfd;
char mesg[MAXLEN];
char reply[MAXLEN];
int port = PORT;
signal(SIGPIPE, sigHlr);
if ((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
{
cout << "client : socket error.\n";
exit(1);
}
bzero((char *)&serv,sizeof(serv));
serv.sin_family = AF_INET;
serv.sin_addr.s_addr = inet_addr("127.0.0.1");
serv.sin_port = htons(port);
if( argc == 2 )
{
serv.sin_addr.s_addr = inet_addr("127.0.0.1");
port = atoi(argv[1]);
serv.sin_port = htons(port);
}
else if ( argc == 3 )
{
serv.sin_addr.s_addr = inet_addr(argv[2]);
port = atoi(argv[1]);
serv.sin_port = htons(port);
}
if ( connect(sockfd,(struct sockaddr *)&serv,sizeof(serv)) < 0)
{
cout << "client : connect error.\n";
exit(1);
}
cout << "Client connected to server successfully at port:" << port << endl;
while(1)
{
cout << endl << "Enter message to server : (Enter q to quit)" << endl;
cin.getline(mesg,MAXLEN,'\n');
if( strcmp(mesg,"q") == 0 )
{
close(sockfd);
break;
}
cout << "Message sending is: " << mesg <<endl;
if ( send(sockfd,mesg,strlen(mesg)+1,0) < 0 || errno == -1 )
{
perror("send");
//close(sockfd);
//exit(1);
// for implementing redundancy at MMI client
sleep(10);
if ((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
{
cout << "client : socket error.\n";
exit(1);
}
bzero((char *)&serv,sizeof(serv));
serv.sin_family = AF_INET;
serv.sin_addr.s_addr = inet_addr("127.0.0.1");
serv.sin_port = htons(port);
if( argc == 2 )
{
serv.sin_addr.s_addr = inet_addr("127.0.0.1");
port = atoi(argv[1]);
serv.sin_port = htons(port);
}
else if ( argc == 3 )
{
serv.sin_addr.s_addr = inet_addr(argv[2]);
port = atoi(argv[1]);
serv.sin_port = htons(port);
}
if ( connect(sockfd,(struct sockaddr *)&serv,sizeof(serv)) < 0)
{
cout << "client : connect error.\n";
exit(1);
}
}
/*
if ( recv(sockfd,&reply,MAXLEN,0) < 0 )
{
perror("recv");
close(sockfd);
exit(1);
}
cout << endl << "client: Received message " << endl;
cout << "Message is : " << reply <<endl;
*/
}
close(sockfd);
}
//============================================================================
// End of tcpClient.cpp
//============================================================================
server:
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/errno.h>
using namespace std;
int STRLEN = 1024;
int PORT = 20000;
int main( int argc, char *argv[])
{
int sockfd;
int newsockfd;
int clilen;
struct sockaddr_in serv,cli;
int chpid;
char buf[STRLEN],ack[STRLEN];
int port = PORT;
if ( argc == 2 )
{
port = atoi(argv[1]);
}
if ((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
{
perror("socket");
exit(0);
}
bzero((char *)&serv,sizeof(serv)) ;
serv.sin_family = AF_INET;
serv.sin_addr.s_addr = htonl(INADDR_ANY);
serv.sin_port = htons(port);
if (bind(sockfd,(struct sockaddr *)&serv,sizeof(serv)) < 0)
{
perror("bind");
exit(1);
}
listen(sockfd,5);
while (1)
{
clilen = sizeof(cli);
cout << "Server waiting for connection request from client " << endl;
if ( (newsockfd = accept(sockfd,(struct sockaddr *)&cli,(socklen_t *)&clilen)) < 0 )
{
perror("accept");
close(sockfd);
exit(1);
}
cout << "server : accepted connection from client at port: " << cli.sin_port <<endl;
if( (chpid = fork()) == 0 )
{
//Child Process
//Handle request and exit
cout << "I am child process on server .. I reply for your request " << endl;
close(sockfd);
while ( recv(newsockfd,&buf, STRLEN, 0) > 0 )
{
cout << endl << "server : received message " <<endl;
cout << "Message is :" << buf << endl;
sprintf(ack,"%s ACK",buf);
cout << endl << "server sending message to client" << endl;
cout << "Message is :" << ack << endl;
if ( send(newsockfd,ack,strlen(ack)+1,0) < 0 )
{
perror("send");
close(newsockfd);
exit(1);
}
}
close(newsockfd);
cout << "Child is exiting" << endl;
exit(1);
}
else if(chpid < 0 )
{
cout << "Fork error\n";
exit(1);
}
else
{
//Parent process
close(newsockfd);
}
}
}
//============================================================================
// End of tcpServer.cpp
//============================================================================
