2009-03-21 20:43:56 +00:00
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.\" Copyright (c) 1994, 1996, 1997
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.\" The Regents of the University of California. All rights reserved.
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.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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.\"
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2017-02-12 07:04:44 +00:00
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.TH PCAP_SETNONBLOCK 3PCAP "18 October 2014"
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2009-03-21 20:43:56 +00:00
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.SH NAME
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pcap_setnonblock, pcap_getnonblock \- set or get the state of
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non-blocking mode on a capture device
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.SH SYNOPSIS
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.nf
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.ft B
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#include <pcap/pcap.h>
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.ft
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.LP
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.nf
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.ft B
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char errbuf[PCAP_ERRBUF_SIZE];
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.ft
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.LP
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.ft B
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int pcap_setnonblock(pcap_t *p, int nonblock, char *errbuf);
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int pcap_getnonblock(pcap_t *p, char *errbuf);
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.ft
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.fi
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.SH DESCRIPTION
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.B pcap_setnonblock()
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puts a capture handle into ``non-blocking'' mode, or takes it out
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of ``non-blocking'' mode, depending on whether the
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.I nonblock
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argument is non-zero or zero. It has no effect on ``savefiles''.
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If there is an error, \-1 is returned and
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.I errbuf
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is filled in with an appropriate error message; otherwise, 0 is
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returned.
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In
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``non-blocking'' mode, an attempt to read from the capture descriptor
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with
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.B pcap_dispatch()
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will, if no packets are currently available to be read, return 0
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immediately rather than blocking waiting for packets to arrive.
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.B pcap_loop()
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and
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.B pcap_next()
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will not work in ``non-blocking'' mode.
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2017-02-12 07:04:44 +00:00
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.PP
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When first activated with
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.B pcap_activate()
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or opened with
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.B pcap_open_live() ,
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a capture handle is not in ``non-blocking mode''; a call to
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.B pcap_setnonblock()
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is required in order to put it into ``non-blocking'' mode.
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2009-03-21 20:43:56 +00:00
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.SH RETURN VALUE
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.B pcap_getnonblock()
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returns the current ``non-blocking'' state of the capture descriptor; it
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always returns 0 on ``savefiles''.
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If there is an error, \-1 is returned and
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.I errbuf
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is filled in with an appropriate error message.
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.PP
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.I errbuf
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is assumed to be able to hold at least
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.B PCAP_ERRBUF_SIZE
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chars.
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.SH SEE ALSO
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pcap(3PCAP), pcap_loop(3PCAP), pcap_next_ex(3PCAP), pcap_geterr(3PCAP)
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