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()
that has not yet been activated by pcap_activate().
http://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 even if all devices on the system
at the time the "any" device is opened have some other data link
type, such as DLT_EN10MB for Ethernet.
This page is part of the libpcap (packet capture library) project.
Information about the project can be found at
⟨http://www.tcpdump.org/⟩. If you have a bug report for this manual
page, see ⟨http://www.tcpdump.org/#patches⟩. This page was obtained
from the project's upstream Git repository
⟨https://github.com/the-tcpdump-group/libpcap.git⟩ on 2017-03-13. If
you discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for the
page, or you have corrections or improvements to the information in
this COLOPHON (which is not part of the original manual page), send a
mail to email@example.com
7 April 2014 PCAP_DATALINK(3PCAP)