C/Zombies
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(Difference between revisions)
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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 <code>sock</code> is the file descriptor that you wish to read from<br> | |
− | + | * <code>children</code> is incremented when you call fork() | |
<pre> | <pre> | ||
/* tidy up after children, but accept new data if its there! */ | /* tidy up after children, but accept new data if its there! */ |
Revision as of 12:31, 3 March 2010
The code below will quickly tidy up after zombie children, and at the same time check for incoming data.
- Assume
sock
is the file descriptor that you wish to read from
-
children
is incremented when you call fork()
/* 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, then we dont need to be here anymore... */ if (!children) break; /* 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; } }