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ares_process

NAME

ares_process - Process events for name resolution

SYNOPSIS

 #include <ares.h>
 
 void ares_process(ares_channel channel, fd_set *read_fds,
 

void ares_process_fd(ares_channel channel, ares_socket_t read_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 with a timeout no greater than the timeout given by ares_timeout(3) ).

The ares_process 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 of course provided to allow users of c-ares to void select() in their applications and within c-ares.

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.