pcap_open_dead(3)

pcap_open_dead3

Open a fake pcap_t for compiling filters or opening a capture for output

Usage

#include <pcap/pcap.h>

pcap_t *pcap_open_dead(int linktype, int snaplen); pcap_t *pcap_open_dead_with_tstamp_precision(int linktype, int snaplen,
u_int precision);

Overview

pcap_open_dead() and pcap_open_dead_with_tstamp_precision() are used for creating a 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 pcap_dump_open(3), pcap_dump(3), and pcap_dump_close(3) to write a savefile if there is no pcap_t that supplies the packets to be written.

linktype specifies the link-layer type for the pcap_t.

snaplen specifies the snapshot length for the pcap_t.

When pcap_open_dead_with_tstamp_precision(), is used to create a pcap_t for use with pcap_dump_open(), precision specifies the time stamp precision for packets; PCAP_TSTAMP_PRECISION_MICRO should be specified if the packets to be written have time stamps in seconds and microseconds, and 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 pcap_compile(3).

Backward compatibility

The 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.

Releases

39 releases since FreeBSD 8.0-RELEASE; the text changed 7 times.

  1. 8.0–9.0
  2. 9.1–10.4
  3. 11.0–11.2
  4. 11.3
  5. 11.4
  6. 12.0–12.1
  7. 12.2–13.4
  8. 13.5–16.0

From base 16.0-CURRENT-20261027-61c70dc16a79 in FreeBSD 16.0-CURRENT (2026-10-27). Parsed by carta from the page's man source.