ares_process(3) [debian man page]

ARES_PROCESS(3) 					     Library Functions Manual						   ARES_PROCESS(3)

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 identi-
       fied 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.

								   25 July 1998 						   ARES_PROCESS(3)

ARES_GETHOSTBYADDR(3)					     Library Functions Manual					     ARES_GETHOSTBYADDR(3)

NAME

       ares_gethostbyaddr - Initiate a host query by address

SYNOPSIS

       #include <ares.h>

       typedef void (*ares_host_callback)(void *arg, int status,
       int timeouts, struct hostent *hostent)

       void ares_gethostbyaddr(ares_channel channel, const void *addr,
	    int addrlen, int family, ares_host_callback callback,
	    void *arg)

DESCRIPTION

       The  ares_gethostbyaddr	function initiates a host query by address on the name service channel identified by channel.  The parameters addr
       and addrlen give the address as a series of bytes, and family gives the type of address.  When the query is complete  or  has  failed,  the
       ares  library  will  invoke  callback.	Completion  or	failure  of the query may happen immediately, or may happen during a later call to
       ares_process(3), ares_destroy(3) or ares_cancel(3).

       The callback argument arg is copied from the ares_gethostbyaddr argument arg.  The callback argument status  indicates  whether	the  query
       succeeded and, if not, how it failed.  It may have any of the following values:

       ARES_SUCCESS	  The host lookup completed successfully.

       ARES_ENOTIMP	  The ares library does not know how to look up addresses of type family.

       ARES_ENOTFOUND	  The address addr was not found.

       ARES_ENOMEM	  Memory was exhausted.

       ARES_ECANCELLED	  The query was cancelled.

       ARES_EDESTRUCTION  The name service channel channel is being destroyed; the query will not be completed.

       The callback argument timeouts reports how many times a query timed out during the execution of the given request.

       On successful completion of the query, the callback argument hostent points to a struct hostent containing the name of the host returned by
       the query.  The callback need not and should not attempt to free the memory pointed to by hostent; the ares library will free it  when  the
       callback returns.  If the query did not complete successfully, hostent will be NULL.

SEE ALSO

       ares_process(3), ares_gethostbyname(3)

AUTHOR

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

								   24 July 1998 					     ARES_GETHOSTBYADDR(3)