The Tcpdump Group git mirrors - libpcap/blob - pcap_lookupdev.3pcap

   1 .\" Copyright (c) 1994, 1996, 1997
   2 .\"     The Regents of the University of California.  All rights reserved.
   3 .\"
   4 .\" Redistribution and use in source and binary forms, with or without
   5 .\" modification, are permitted provided that: (1) source code distributions
   6 .\" retain the above copyright notice and this paragraph in its entirety, (2)
   7 .\" distributions including binary code include the above copyright notice and
   8 .\" this paragraph in its entirety in the documentation or other materials
   9 .\" provided with the distribution, and (3) all advertising materials mentioning
  10 .\" features or use of this software display the following acknowledgement:
  11 .\" ``This product includes software developed by the University of California,
  12 .\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  13 .\" the University nor the names of its contributors may be used to endorse
  14 .\" or promote products derived from this software without specific prior
  15 .\" written permission.
  16 .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  17 .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  18 .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  19 .\"
  20 .TH PCAP_LOOKUPDEV 3PCAP "8 September 2017"
  21 .SH NAME
  22 pcap_lookupdev \- find the default device on which to capture
  23 .SH SYNOPSIS
  24 .nf
  25 .ft B
  26 #include <pcap/pcap.h>
  27 .ft
  28 .LP
  29 .nf
  30 .ft B
  31 char errbuf[PCAP_ERRBUF_SIZE];
  32 .ft
  33 .LP
  34 .ft B
  35 [DEPRECATED] char *pcap_lookupdev(char *errbuf);
  36 .ft
  37 .fi
  38 .SH DESCRIPTION
  39 .B This interface is obsoleted by
  40 .BR pcap_findalldevs (3PCAP).
  41 To find a default device on which to capture, call
  42 .BR pcap_findalldevs ()
  43 and, if the list it returns is not empty, use the first device in the
  44 list.  (If the list is empty, there are no devices on which capture is
  45 possible.)
  46 .LP
  47 .B If
  48 .BR pcap_init (3PCAP)
  49 .B has been called, this interface always returns
  50 .BR NULL .
  51 .LP
  52 .BR pcap_lookupdev ()
  53 returns a pointer to a string giving the name of a network device
  54 suitable for use with
  55 .BR pcap_create (3PCAP)
  56 and
  57 .BR \%pcap_activate (3PCAP),
  58 or with
  59 .BR pcap_open_live (3PCAP),
  60 and with
  61 .BR pcap_lookupnet (3PCAP).
  62 If there is an error,
  63 or if
  64 .BR pcap_init (3PCAP)
  65 has been called,
  66 .B NULL
  67 is returned and
  68 .I errbuf
  69 is filled in with an appropriate error message.
  70 .I errbuf
  71 is assumed to be able to hold at least
  72 .B PCAP_ERRBUF_SIZE
  73 chars.
  74 .SH SEE ALSO
  75 .BR pcap (3PCAP)
  76 .SH BUGS
  77 The pointer returned by
  78 .BR pcap_lookupdev ()
  79 points to a static buffer; subsequent calls to
  80 .BR pcap_lookupdev ()
  81 in the same thread, or calls to
  82 .BR pcap_lookupdev ()
  83 in another thread, may overwrite that buffer.
  84 .LP
  85 In WinPcap and Npcap, this function may return a UTF-16 string rather
  86 than an ASCII or UTF-8 string.