pcap_set_datalink.3pcap - Man Page

#include <pcap/pcap.h>

int pcap_set_datalink(pcap_t *p, int dlt);

pcap_set_datalink() is used to set the current link-layer header type of the pcap descriptor to the type specified by dlt.

pcap_set_datalink() 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(3PCAP) or pcap_perror(3PCAP) may be called with p as an argument to fetch or display the error text.

pcap(3PCAP), pcap_datalink_name_to_val(3PCAP)