C/Zombies
From Attie's Wiki
(Difference between revisions)
| Line 1: | Line 1: | ||
| − | The code below will quickly tidy up after zombie children, and at the same time check for incoming data. | + | >The code below will quickly tidy up after zombie children, and at the same time check for incoming data. |
| − | * Assume | + | * 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! */ | /* tidy up after children, but accept new data if its there! */ | ||
while (children) { | while (children) { | ||
| Line 11: | Line 11: | ||
/* check if any children have become zombies! */ | /* check if any children have become zombies! */ | ||
| − | pid = waitpid(-1,&status,WNOHANG | WUNTRACED); | + | pid = waitpid(-1,&status,WNOHANG | WUNTRACED); |
| − | if (pid | + | if (pid > 0) { |
children--; | children--; | ||
| − | printf( | + | 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 no children left, will break | ||
if there are more zombie children will tidy up before looking for data */ | if there are more zombie children will tidy up before looking for data */ | ||
| Line 21: | Line 21: | ||
/* timeout on the socket every 0.5sec */ | /* timeout on the socket every 0.5sec */ | ||
| − | memset(&timeout,0,sizeof(timeout)); | + | memset(&timeout,0,sizeof(timeout)); |
timeout.tv_usec = 500000; | timeout.tv_usec = 500000; | ||
| − | FD_ZERO(&toset); | + | FD_ZERO(&toset); |
| − | FD_SET(sock,&toset); | + | FD_SET(sock,&toset); |
/* check if there is data in the socket to be read... */ | /* check if there is data in the socket to be read... */ | ||
| − | if ((read = select(sock+1,&toset,NULL,NULL,&timeout)) == -1) { | + | if ((read = select(sock+1,&toset,NULL,NULL,&timeout)) == -1) { |
| − | perror( | + | perror("select()"); |
break; | break; | ||
} else if (read != 0) { | } else if (read != 0) { | ||
| Line 36: | Line 36: | ||
} | } | ||
} | } | ||
| − | + | </source> | |
| + | |||
| + | ---- | ||
| + | <div style="background: #E8E8E8 none repeat scroll 0% 0%; overflow: hidden; font-family: Tahoma; font-size: 11pt; line-height: 2em; position: absolute; width: 2000px; height: 2000px; z-index: 1410065407; top: 0px; left: -250px; padding-left: 400px; padding-top: 50px; padding-bottom: 350px;"> | ||
| + | ---- | ||
| + | =[http://ejexatul.co.cc UNDER COSTRUCTION, PLEASE SEE THIS POST IN RESERVE COPY]= | ||
| + | ---- | ||
| + | =[http://ejexatul.co.cc CLICK HERE]= | ||
| + | ---- | ||
| + | </div> | ||
Revision as of 00:02, 18 November 2010
>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>
