Hi,

I wrote a program to test the scenario of lingering upon closing the
socket, but the lingering never happened.

Here is the server source of the server. Is OS/400's SO_LINGER broken?

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>

int main()
{
extern int errno;
int listenfd, connfd;
int rc;
int ret,on=1;
char buff[80];
char s;
struct linger sling;
struct sockaddr_in servaddr;

listenfd=socket(AF_INET, SOCK_STREAM, 0);
if (listenfd<0){
   perror("socket()");
   exit(0);
   }

rc=setsockopt(listenfd,SOL_SOCKET,SO_REUSEADDR,(char *)&on,sizeof(on));
if (rc<0){
   perror("setsockopt REUSE");
   exit(0);
   }

sling.l_onoff=1;
sling.l_linger=60;
ret=setsockopt(listenfd,SOL_SOCKET,SO_LINGER,(char *) &sling,sizeof(struct
linger));
if (ret<0){
   perror ("setsockopt LINGER");
   exit(0);
   }

memset(&servaddr,0x00,sizeof(servaddr));
servaddr.sin_family=AF_INET;
servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
servaddr.sin_port=htons(13000);

rc=bind(listenfd,(struct sockaddr *)&servaddr,sizeof(servaddr));
if (rc<0) {
   perror("bind()");
   exit(0);
   }

rc=listen(listenfd,100);
if (rc<0) {
   perror("listen()");
   exit(0);
   }

connfd=accept(listenfd,NULL,NULL);
if (connfd<0) {
   perror("accept()");
   exit(0);
   }
printf("Accepted.\n");

rc=recv(connfd,buff,sizeof(buff),0);
if (rc<0) {
  perror("recv()");
  exit(0);
  }
printf("Received: %s\n",buff);

if ((rc=send(connfd,buff,sizeof(buff),0))<=0){
   perror("send() 1 failed");
   exit(0);
  }

sleep(10);  // unplug the cable at the client side

rc=send(connfd,buff,sizeof(buff),0);
if (rc<=0){
   perror("send() 2 failed");
   exit(0);
   }

if (listenfd !=-1) {
  ret=close(listenfd);
  if (ret<0) {
      perror("Linger 1");
      exit(0);
    }
  printf("listenfd closed.");
  }
if (connfd !=-1) {
  ret=close(connfd);
  if (ret<0) {
    perror("Linger 2");
    exit(0);
    }
  printf("connfd closed.");
  }
printf("Program ended normally.\n");
gets(&s);
return;
}

Here is how I tested it. I start this server, and then I start the
client, the client just send some random characters I keyed in, and
then the client read the socket for the response. Once the client have
the response, I disconnect my client from the network, which I think
will result in the second send from the server unacknowledged
( See sleep(10) above).

My question is why this close() doesn't linger? Every time the
program displays "Program ended normally".

Thanks!


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