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1 office 1 .\" Copyright (c) 1994, 1996, 1997
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16 .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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20 .TH PCAP_STATS 3PCAP "7 September 2009"
21 .SH NAME
22 pcap_stats \- get capture statistics
23 .SH SYNOPSIS
24 .nf
25 .ft B
26 #include <pcap/pcap.h>
27 .ft
28 .LP
29 .ft B
30 int pcap_stats(pcap_t *p, struct pcap_stat *ps);
31 .ft
32 .fi
33 .SH DESCRIPTION
34 .B pcap_stats()
35 fills in the
36 .B struct pcap_stat
37 pointed to by its second argument. The values represent
38 packet statistics from the start of the run to the time of the call.
39 .PP
40 .B pcap_stats()
41 is supported only on live captures, not on ``savefiles''; no statistics
42 are stored in ``savefiles'', so no statistics are available when reading
43 from a ``savefile''.
44 .PP
45 A
46 .B struct pcap_stat
47 has the following members:
48 .RS
49 .TP
50 .B ps_recv
51 number of packets received;
52 .TP
53 .B ps_drop
54 number of packets dropped because there was no room in the operating
55 system's buffer when they arrived, because packets weren't being read
56 fast enough;
57 .TP
58 .B ps_ifdrop
59 number of packets dropped by the network interface or its driver.
60 .RE
61 .PP
62 The statistics do not behave the same way on all platforms.
63 .B ps_recv
64 might count packets whether they passed any filter set with
65 .BR pcap_setfilter (3PCAP)
66 or not, or it might count only packets that pass the filter.
67 It also might, or might not, count packets dropped because there was no
68 room in the operating system's buffer when they arrived.
69 .B ps_drop
70 is not available on all platforms; it is zero on platforms where it's
71 not available. If packet filtering is done in libpcap, rather than in
72 the operating system, it would count packets that don't pass the filter.
73 Both
74 .B ps_recv
75 and
76 .B ps_drop
77 might, or might not, count packets not yet read from the operating
78 system and thus not yet seen by the application.
79 .B ps_ifdrop
80 might, or might not, be implemented; if it's zero, that might mean that
81 no packets were dropped by the interface, or it might mean that the
82 statistic is unavailable, so it should not be treated as an indication
83 that the interface did not drop any packets.
84 .SH RETURN VALUE
85 .B pcap_stats()
86 returns 0 on success and returns \-1 if there is an error or if
87 .I p
88 doesn't support packet statistics.
89 If \-1 is returned,
90 .B pcap_geterr()
91 or
92 .B pcap_perror()
93 may be called with
94 .I p
95 as an argument to fetch or display the error text.
96 .SH SEE ALSO
97 pcap(3PCAP), pcap_geterr(3PCAP)