PCAP_LOOKUPDEV(3)      FreeBSD Library Functions Manual      PCAP_LOOKUPDEV(3)

NAME

     pcap_lookupdev - find the default device on which to capture

SYNOPSIS

     #include <pcap/pcap.h>

     char errbuf[PCAP_ERRBUF_SIZE];

     [DEPRECATED] char *pcap_lookupdev(char *errbuf);

DESCRIPTION

     This interface is obsoleted by pcap_findalldevs(3).  To find a default
     device on which to capture, call pcap_findalldevs() and, if the list it
     returns is not empty, use the first device in the list.  (If the list is
     empty, there are no devices on which capture is possible.)  errbuf is a
     buffer large enough to hold at least PCAP_ERRBUF_SIZE chars.

     If pcap_init(3) has been called, this interface always returns NULL.

     pcap_lookupdev() returns a pointer to a string giving the name of a
     network device suitable for use with pcap_create(3) and pcap_activate(3),
     or with pcap_open_live(3), and with pcap_lookupnet(3).  If there is an
     error, or if pcap_init(3) has been called, NULL is returned and errbuf is
     filled in with an appropriate error message.

SEE ALSO

     pcap(3)

BUGS

     The pointer returned by pcap_lookupdev() points to a static buffer;
     subsequent calls to pcap_lookupdev() in the same thread, or calls to
     pcap_lookupdev() in another thread, may overwrite that buffer.

     In WinPcap and Npcap, this function may return a UTF-16 string rather
     than an ASCII or UTF-8 string.

                               30 November 2023              PCAP_LOOKUPDEV(3)