ARES_PROCESS(3)ARES_PROCESS(3)NAMEares_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 with a timeout no greater than the timeout given by ares_time‐
out(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 ALSOares_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)
