1PCAP_OPEN_OFFLINE(3PCAP)                              PCAP_OPEN_OFFLINE(3PCAP)
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NAME

6       pcap_open_offline,             pcap_open_offline_with_tstamp_precision,
7       pcap_fopen_offline, pcap_fopen_offline_with_tstamp_precision -  open  a
8       saved capture file for reading
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SYNOPSIS

11       #include <pcap/pcap.h>
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13       char errbuf[PCAP_ERRBUF_SIZE];
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15       pcap_t *pcap_open_offline(const char *fname, char *errbuf);
16       pcap_t *pcap_open_offline_with_tstamp_precision(const char *fname,
17           u_int precision, char *errbuf);
18       pcap_t *pcap_fopen_offline(FILE *fp, char *errbuf);
19       pcap_t *pcap_fopen_offline_with_tstamp_precision(FILE *fp,
20           u_int precision, char *errbuf);
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DESCRIPTION

23       pcap_open_offline()  and  pcap_open_offline_with_tstamp_precision() are
24       called to open a ``savefile'' for reading.
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26       fname specifies the name of the file to open. The  file  can  have  the
27       pcap  file  format  as described in pcap-savefile(5), which is the file
28       format used by, among other programs, tcpdump(1)  and  tcpslice(1),  or
29       can  have  the pcapng file format, although not all pcapng files can be
30       read.  The name "-" is a synonym for stdin.
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32       pcap_open_offline_with_tstamp_precision() takes an additional precision
33       argument    specifying   the   time   stamp   precision   desired;   if
34       PCAP_TSTAMP_PRECISION_MICRO is specified, packet time  stamps  will  be
35       supplied in seconds and microseconds, and if PCAP_TSTAMP_PRECISION_NANO
36       is specified, packet time  stamps  will  be  supplied  in  seconds  and
37       nanoseconds.   If the time stamps in the file do not have the same pre‐
38       cision as the requested precision, they will be scaled up  or  down  as
39       necessary before being supplied.
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41       Alternatively,  you  may  call  pcap_fopen_offline() or pcap_fopen_off‐
42       line_with_tstamp_precision() to read dumped data from an existing  open
43       stream  fp.   pcap_fopen_offline_with_tstamp_precision() takes an addi‐
44       tional precision argument as described above.  Note  that  on  Windows,
45       that stream should be opened in binary mode.
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RETURN VALUE

48       pcap_open_offline(),         pcap_open_offline_with_tstamp_precision(),
49       pcap_fopen_offline(),  and   pcap_fopen_offline_with_tstamp_precision()
50       return a pcap_t * on success and NULL on failure.  If NULL is returned,
51       errbuf is filled in with an appropriate error message.  errbuf  is  as‐
52       sumed to be able to hold at least PCAP_ERRBUF_SIZE chars.
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BACKWARD COMPATIBILITY

55       pcap_open_offline_with_tstamp_precision()      and      pcap_fopen_off‐
56       line_with_tstamp_precision() became available in libpcap release 1.5.1.
57       In  previous  releases, time stamps from a savefile are always given in
58       seconds and microseconds.
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SEE ALSO

61       pcap(3PCAP), pcap-savefile(5)
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65                                23 August 2018        PCAP_OPEN_OFFLINE(3PCAP)
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