Manual Pages  — PCAP_LIST_DATALINKS

pcap_list_datalinks, pcap_free_datalinks - get a list of link-layer header types supported by a capture device, and free that list

SYNOPSIS DESCRIPTION RETURN VALUE SEE ALSO

#include <pcap/pcap.h>

int pcap_list_datalinks(pcap_t *p, int **dlt_buf);
void pcap_free_datalinks(int *dlt_list);

pcap_list_datalinks() is used to get a list of the supported link-layer header types of the interface associated with the pcap descriptor. pcap_list_datalinks() allocates an array to hold the list and sets *dlt_buf to point to that array.

The caller is responsible for freeing the array with pcap_free_datalinks(), which frees the list of link-layer header types pointed to by dlt_list.

It must not be called on a pcap descriptor created by  pcap_create(3) that has not yet been activated by  pcap_activate(3) .

pcap_list_datalinks() returns the number of link-layer header types in the array on success, PCAP_ERROR_NOT_ACTIVATED if called on a capture handle that has been created but not activated, and 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.