NAME

       ares_process - Process events for name resolution

SYNOPSIS

       #include <ares.h>

       void ares_process(ares_channel channel,
                         fd_set *read_fds,
                         fd_set *write_fds)

       void ares_process_fd(ares_channel channel,
                            ares_socket_t read_fd,
                            ares_socket_t write_fd)

DESCRIPTION

       The  ares_process(3)  function  handles  input/output  events and timeouts associated with
       queries pending on the name service channel identified by channel.   The  file  descriptor
       sets  pointed  to  by  read_fds  and  write_fds  should  have file descriptors set in them
       according to whether the file descriptors specified by ares_fds(3) are ready  for  reading
       and writing.  (The easiest way to determine this information is to invoke select(3) with a
       timeout no greater than the timeout given by ares_timeout(3)).

       The ares_process(3) function will invoke callbacks for pending queries  if  they  complete
       successfully or fail.

       ares_process_fd(3)  works  the  same  way  but acts and operates only on the specific file
       descriptors (sockets) you pass in to the function. Use ARES_SOCKET_BAD  for  "no  action".
       This function is provided to allow users of c-ares to void select(3) in their applications
       and within c-ares.

       To only process possible timeout conditions without a socket event occurring, one may pass
       NULL as the values for both read_fds and write_fds for ares_process(3), or ARES_SOCKET_BAD
       for both read_fd and write_fd for ares_process_fd(3).

EXAMPLE

       The following code fragment waits for all pending queries on a channel to complete:

       int nfds, count;
       fd_set readers, writers;
       struct timeval tv, *tvp;

       while (1) {
         FD_ZERO(&readers);
         FD_ZERO(&writers);
         nfds = ares_fds(channel, &readers, &writers);
         if (nfds == 0)
           break;
         tvp = ares_timeout(channel, NULL, &tv);
         count = select(nfds, &readers, &writers, NULL, tvp);
         ares_process(channel, &readers, &writers);
       }

SEE ALSO

       ares_fds(3), ares_timeout(3)

AUTHOR

       Greg Hudson, MIT Information Systems
       Copyright 1998 by the Massachusetts Institute of Technology.

                                           25 July 1998                           ARES_PROCESS(3)