73ef4ff3
 Hu Chunming
提交三方库
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.\"
.\" Copyright 1998 by the Massachusetts Institute of Technology.
.\"
.\" Permission to use, copy, modify, and distribute this
.\" software and its documentation for any purpose and without
.\" fee is hereby granted, provided that the above copyright
.\" notice appear in all copies and that both that copyright
.\" notice and this permission notice appear in supporting
.\" documentation, and that the name of M.I.T. not be used in
.\" advertising or publicity pertaining to distribution of the
.\" software without specific, written prior permission.
.\" M.I.T. makes no representations about the suitability of
.\" this software for any purpose. It is provided "as is"
.\" without express or implied warranty.
.\"
.TH ARES_GETHOSTBYNAME 3 "25 July 1998"
.SH NAME
ares_gethostbyname_file \- Lookup a name in the system's hosts file
.SH SYNOPSIS
.nf
.B #include <ares.h>
.PP
.B int ares_gethostbyname_file(ares_channel \fIchannel\fP, const char *\fIname\fP,
.B int \fIfamily\fP, struct hostent **host)
.fi
.SH DESCRIPTION
The
.B ares_gethostbyname_file
function performs a host lookup by name against the system's hosts file (or equivalent local hostname database).
The
.IR channel
parameter is required, but no asynchronous queries are performed. Instead, the
lookup is done via the same mechanism used to perform 'f' lookups
(see the
.I lookups
options field in \fIares_init_options(3)\fP).
The parameter
.I name
gives the hostname as a NUL-terminated C string, and
.I family
gives the desired type of address for the resulting host entry.
.PP
The return value indicates whether the query succeeded and, if not, how it
failed. It may have any of the following values:
.TP 19
.B ARES_SUCCESS
The host lookup completed successfully and
.I host
now points to the result (and must be freed with \fIares_free_hostent(3)\fP).
.TP 19
.B ARES_ENOTFOUND
The hostname
.I name
was not found.
.TP 19
.B ARES_EFILE
There was a file I/O error while performing the lookup.
.TP 19
.B ARES_ENOMEM
Memory was exhausted.
.PP
On successful completion of the query, the pointer pointed to by
.I host
points to a
.B struct hostent
containing the address of the host returned by the lookup. The user must
free the memory pointed to by
.IR host
when finished with it by calling \fIares_free_hostent(3)\fP. If the lookup did
not complete successfully,
.I host
will be
.BR NULL .
.SH AVAILABILITY
Added in c-ares 1.5.4
.SH SEE ALSO
.BR ares_gethostbyname (3),
.BR ares_free_hostent (3),
.BR ares_init_options (3)
.SH AUTHOR
Brad Spencer
.br
Copyright 1998 by the Massachusetts Institute of Technology.
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