.\" @(#) $Header: /tcpdump/master/libpcap/pcap_open_live.3pcap,v 1.1.2.3 2008-04-06 03:21:56 guy Exp $ .\" .\" Copyright (c) 1994, 1996, 1997 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that: (1) source code distributions .\" retain the above copyright notice and this paragraph in its entirety, (2) .\" distributions including binary code include the above copyright notice and .\" this paragraph in its entirety in the documentation or other materials .\" provided with the distribution, and (3) all advertising materials mentioning .\" features or use of this software display the following acknowledgement: .\" ``This product includes software developed by the University of California, .\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of .\" the University nor the names of its contributors may be used to endorse .\" or promote products derived from this software without specific prior .\" written permission. .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. .\" .TH PCAP_OPEN_LIVE 3PCAP "5 April 2008" .SH NAME pcap_open_live \- open a device for capturing .SH SYNOPSIS .nf .ft B #include .ft .LP .nf .ft B char errbuf[PCAP_ERRBUF_SIZE]; .ft .LP .ft B pcap_t *pcap_open_live(const char *device, int snaplen, .ti +8 int promisc, int to_ms, char *errbuf); .ft .fi .SH DESCRIPTION .B pcap_open_live() is used to obtain a packet capture handle to look at packets on the network. .I device is a string that specifies the network device to open; on Linux systems with 2.2 or later kernels, a .I device argument of "any" or .B NULL can be used to capture packets from all interfaces. .PP .I snaplen specifies the snapshot length to be set on the handle. .PP .I promisc specifies if the interface is to be put into promiscuous mode. .PP .I to_ms specifies the read timeout in milliseconds. .SH RETURN VALUE .B pcap_open_live() returns a .I pcap_t * on success and .B NULL on failure. If .B NULL is returned, .I errbuf is filled in with an appropriate error message. .I errbuf may also be set to warning text when .B pcap_open_live() succeds; to detect this case the caller should store a zero-length string in .I errbuf before calling .B pcap_open_live() and display the warning to the user if .I errbuf is no longer a zero-length string. .I errbuf is assumed to be able to hold at least .B PCAP_ERRBUF_SIZE chars. .SH SEE ALSO pcap(3PCAP), pcap_create(3PCAP), pcap_activate(3PCAP)