.\" @(#) $Header: /tcpdump/master/libpcap/pcap_list_datalinks.3pcap.in,v 1.1 2008-10-21 07:33:02 guy Exp $
.\"
.\" Copyright (c) 1994, 1996, 1997
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that: (1) source code distributions
.\" retain the above copyright notice and this paragraph in its entirety, (2)
.\" distributions including binary code include the above copyright notice and
.\" this paragraph in its entirety in the documentation or other materials
.\" provided with the distribution, and (3) all advertising materials mentioning
.\" features or use of this software display the following acknowledgement:
.\" ``This product includes software developed by the University of California,
.\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
.\" the University nor the names of its contributors may be used to endorse
.\" or promote products derived from this software without specific prior
.\" written permission.
.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
.\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
.\"
.TH PCAP_LIST_DATALINKS 3PCAP "22 August 2010"
.SH NAME
pcap_list_datalinks, pcap_free_datalinks \- get a list of link-layer header
types supported by a capture device, and free that list
.SH SYNOPSIS
.nf
.ft B
#include <pcap/pcap.h>
.ft
.LP
.ft B
int pcap_list_datalinks(pcap_t *p, int **dlt_buf);
void pcap_free_datalinks(int *dlt_list);
.ft
.fi
.SH DESCRIPTION
.B pcap_list_datalinks()
is used to get a list of the supported link-layer header types of the
interface associated with the pcap descriptor.
.B pcap_list_datalinks()
allocates an array to hold the list and sets
.IR *dlt_buf 
to point to that array.
.LP
The caller is responsible for freeing the array with
.BR pcap_free_datalinks() ,
which frees the list of link-layer header types pointed to by
.IR dlt_list .
.LP
It must not be called on a pcap descriptor created by
.B pcap_create()
that has not yet been activated by
.BR pcap_activate() .
.SH RETURN VALUE
.B pcap_list_datalinks()
returns the number of link-layer header types in the array on success,
.B PCAP_ERROR_NOT_ACTIVATED
if called on a capture handle that has been created but not activated,
and
.B PCAP_ERROR
(\-1) on other errors.
If
.B PCAP_ERROR
is returned,
.B pcap_geterr()
or
.B pcap_perror()
may be called with
.I p
as an argument to fetch or display the error text.
.SH SEE ALSO
pcap(3PCAP), pcap_geterr(3PCAP),
pcap_datalink_val_to_name(3PCAP),
pcap-linktype(@MAN_MISC_INFO@)