pcap_setdirection(3)

pcap_setdirection3

Set the direction for which packets will be captured

Usage

#include <pcap/pcap.h>

int pcap_setdirection(pcap_t *p, pcap_direction_t d);

Overview

pcap_setdirection() is used to specify a direction that packets will be captured. d is one of the constants PCAP_D_IN, PCAP_D_OUT or PCAP_D_INOUT. PCAP_D_IN will only capture packets received by the device, PCAP_D_OUT will only capture packets sent by the device and PCAP_D_INOUT will capture packets received by or sent by the device. PCAP_D_INOUT is the default setting if this function is not called.

pcap_setdirection() isn't necessarily fully supported on all platforms; some platforms might return an error for all values, and some other platforms might not support PCAP_D_OUT.

This operation is not supported if a ``savefile'' is being read.

Return value

pcap_setdirection() returns 0 on success, PCAP_ERROR_NOT_ACTIVATED if called on a capture handle that has been created but not activated, or PCAP_ERROR on other errors. If PCAP_ERROR is returned, pcap_geterr(3) or pcap_perror(3) may be called with p as an argument to fetch or display the error text.

Releases

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

  1. 8.0–8.4
  2. 9.0–10.4
  3. 11.0
  4. 11.1–11.3
  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.