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.TH PCAP_OPEN_DEAD 3PCAP "3 January 2014"
.SH NAME
pcap_open_dead, pcap_open_dead_with_tstamp_precision \- open a fake
pcap_t for compiling filters or opening a capture for output
.SH SYNOPSIS
.nf
.ft B
#include <pcap/pcap.h>
.ft
.LP
.ft B
pcap_t *pcap_open_dead(int linktype, int snaplen);
pcap_t *pcap_open_dead_with_tstamp_precision(int linktype, int snaplen,
    u_int precision);
.ft
.fi
.SH DESCRIPTION
.PP
.BR pcap_open_dead ()
and
.BR pcap_open_dead_with_tstamp_precision ()
are used for creating a
.B pcap_t
structure to use when calling the other functions in libpcap.  It is
typically used when just using libpcap for compiling BPF code; it can
also be used if using
.BR pcap_dump_open (3PCAP),
.BR pcap_dump (3PCAP),
and
.BR pcap_dump_close (3PCAP)
to write a savefile if there is no
.B pcap_t
that supplies the packets to be written.
.PP
.I linktype
specifies the link-layer type for the
.BR pcap_t .
.PP
.I snaplen
specifies the snapshot length for the
.BR pcap_t .
.PP
When
.BR pcap_open_dead_with_tstamp_precision (),
is used to create a
.B pcap_t
for use with
.BR pcap_dump_open (),
.I precision
specifies the time stamp precision for packets;
.B PCAP_TSTAMP_PRECISION_MICRO
should be specified if the packets to be written have time stamps in
seconds and microseconds, and
.B PCAP_TSTAMP_PRECISION_NANO
should be specified if the packets to be written have time stamps in
seconds and nanoseconds.  Its value does not affect
.BR pcap_compile (3PCAP).
.SH BACKWARD COMPATIBILITY
The
.BR pcap_open_dead_with_tstamp_precision ()
function became available in libpcap release 1.5.1.  In previous
releases, there was no mechanism to open a savefile for writing with
time stamps given in seconds and nanoseconds.
.SH SEE ALSO
.BR pcap (3PCAP),
.BR \%pcap-linktype (@MAN_MISC_INFO@)