C/Zombies
From Attie's Wiki
>The code below will quickly tidy up after zombie children, and at the same time check for incoming data.
- Assume <code>sock</code> is the file descriptor that you wish to read from<br>
- <code>children</code> is incremented when you call <code>fork()</code>
<source lang="c"> /* tidy up after children, but accept new data if its there! */ while (children) {
int pid, status, read; struct timeval timeout; fd_set toset;
/* check if any children have become zombies! */
pid = waitpid(-1,&status,WNOHANG | WUNTRACED);
if (pid > 0) {
children--;
printf("*** Child Died *** PID: %-6d Status: %-3d Children: %-2d\n",pid,WEXITSTATUS(status),children);
/* if there are no children left, will break
if there are more zombie children will tidy up before looking for data */
continue;
}
/* timeout on the socket every 0.5sec */ memset(&timeout,0,sizeof(timeout)); timeout.tv_usec = 500000;
FD_ZERO(&toset); FD_SET(sock,&toset);
/* check if there is data in the socket to be read... */
if ((read = select(sock+1,&toset,NULL,NULL,&timeout)) == -1) {
perror("select()");
break;
} else if (read != 0) {
/* something can be read! */
break;
}
} </source>
