1PCAP_DATALINK(3PCAP)                                      PCAP_DATALINK(3PCAP)
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NAME

6       pcap_datalink - get the link-layer header type
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SYNOPSIS

9       #include <pcap/pcap.h>
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11       int pcap_datalink(pcap_t *p);
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DESCRIPTION

14       pcap_datalink() returns the link-layer header type for the live capture
15       or ``savefile'' specified by p.
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17       It must not be called on a pcap  descriptor  created  by  pcap_create()
18       that has not yet been activated by pcap_activate().
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20       https://www.tcpdump.org/linktypes.html lists the values pcap_datalink()
21       can return and describes the packet formats that  correspond  to  those
22       values.
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24       Do NOT assume that the packets for a given capture or ``savefile`` will
25       have any given link-layer header type, such as DLT_EN10MB for Ethernet.
26       For  example,  the  "any" device on Linux will have a link-layer header
27       type of DLT_LINUX_SLL even if all devices on the system at the time the
28       "any"  device  is  opened  have  some  other  data  link  type, such as
29       DLT_EN10MB for Ethernet.
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RETURN VALUE

32       pcap_datalink() returns the  link-layer  header  type  on  success  and
33       PCAP_ERROR_NOT_ACTIVATED  if  called  on a capture handle that has been
34       created but not activated.
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SEE ALSO

37       pcap(3PCAP), pcap-linktype(7)
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41                                 7 April 2014             PCAP_DATALINK(3PCAP)
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