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PCAP_DATALINK(3PCAP)					  PCAP_DATALINK(3PCAP)

NAME
       pcap_datalink - get the link-layer header type

SYNOPSIS
       #include	<pcap/pcap.h>

       int pcap_datalink(pcap_t	*p);

DESCRIPTION
       pcap_datalink() returns the link-layer header type for the live capture
       or ``savefile'' specified by p.

       It   must   not	 be   called   on   a	pcap   descriptor  created  by
       pcap_create(3PCAP)   that   has	 not	yet    been    activated    by
       pcap_activate(3PCAP).

       https://www.tcpdump.org/linktypes.html lists the	values pcap_datalink()
       can  return  and	 describes the packet formats that correspond to those
       values.

       Do NOT assume that the packets for a given capture or ``savefile`` will
       have any	given link-layer header	type, such as DLT_EN10MB for Ethernet.
       For example, the	"any" device on	Linux will have	 a  link-layer	header
       type of DLT_LINUX_SLL or	DLT_LINUX_SLL2 even if all devices on the sys-
       tem  at	the  time the "any" device is opened have some other data link
       type, such as DLT_EN10MB	for Ethernet.

RETURN VALUE
       pcap_datalink() returns the  link-layer	header	type  on  success  and
       PCAP_ERROR_NOT_ACTIVATED	 if  called  on	a capture handle that has been
       created but not activated.

SEE ALSO
       pcap(3PCAP), pcap-linktype(7)

				 7 April 2014		  PCAP_DATALINK(3PCAP)

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