ares_fds.3

这是国外的resip协议栈

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.TH ARES_FDS 3 "23 July 1998"
.SH NAME
ares_fds \- Get file descriptors to select on for name service
.SH SYNOPSIS
.nf
.B #include <ares.h>
.PP
.B int ares_fds(ares_channel \fIchannel\fP, fd_set *\fIread_fds\fP,
.B	fd_set *\fIwrite_fds\fP)
.fi
.SH DESCRIPTION
The
.B ares_fds
function retrieves the set of file descriptors which the calling
application should select on for reading and writing for the
processing of name service queries pending on the name service channel
identified by
.IR channel .
File descriptors will be set in the file descriptor sets pointed to by
.I read_fds
and
.I write_fds
as appropriate.  File descriptors already set in
.I read_fds
and
.I write_fds
will remain set; initialization of the file descriptor sets
(using
.BR FD_ZERO )
is the responsibility of the caller.
.SH RETURN VALUES
.B ares_fds
returns one greater than the number of the highest socket set in either
.I read_fds
or
.IR write_fds .
If no queries are active,
.B ares_fds
will return 0.
.SH SEE ALSO
.BR ares_timeout (3),
.BR ares_process (3)
.SH AUTHOR
Greg Hudson, MIT Information Systems
.br
Copyright 1998 by the Massachusetts Institute of Technology.