pcap_open_offline(3pcap) — Linux manual page



NAME         top

       pcap_open_offline, pcap_open_offline_with_tstamp_precision,
       pcap_fopen_offline, pcap_fopen_offline_with_tstamp_precision -
       open a saved capture file for reading

SYNOPSIS         top

       #include <pcap/pcap.h>

       char errbuf[PCAP_ERRBUF_SIZE];

       pcap_t *pcap_open_offline(const char *fname, char *errbuf);
       pcap_t *pcap_open_offline_with_tstamp_precision(const char *fname,
           u_int precision, char *errbuf);
       pcap_t *pcap_fopen_offline(FILE *fp, char *errbuf);
       pcap_t *pcap_fopen_offline_with_tstamp_precision(FILE *fp,
           u_int precision, char *errbuf);

DESCRIPTION         top

       pcap_open_offline() and pcap_open_offline_with_tstamp_precision()
       are called to open a ``savefile'' for reading.

       fname specifies the name of the file to open. The file can have
       the pcap file format as described in pcap-savefile(5), which is
       the file format used by, among other programs, tcpdump(1) and
       tcpslice(1), or can have the pcapng file format, although not all
       pcapng files can be read.  The name "-" is a synonym for stdin.

       pcap_open_offline_with_tstamp_precision() takes an additional
       precision argument specifying the time stamp precision desired;
       if PCAP_TSTAMP_PRECISION_MICRO is specified, packet time stamps
       will be supplied in seconds and microseconds, and if
       PCAP_TSTAMP_PRECISION_NANO is specified, packet time stamps will
       be supplied in seconds and nanoseconds.  If the time stamps in
       the file do not have the same precision as the requested
       precision, they will be scaled up or down as necessary before
       being supplied.

       Alternatively, you may call pcap_fopen_offline() or
       pcap_fopen_offline_with_tstamp_precision() to read dumped data
       from an existing open stream fp.
       pcap_fopen_offline_with_tstamp_precision() takes an additional
       precision argument as described above.  Note that on Windows,
       that stream should be opened in binary mode.

RETURN VALUE         top

       pcap_open_offline(), pcap_open_offline_with_tstamp_precision(),
       pcap_fopen_offline(), and
       pcap_fopen_offline_with_tstamp_precision() return a pcap_t * on
       success and NULL on failure.  If NULL is returned, errbuf is
       filled in with an appropriate error message.  errbuf is assumed
       to be able to hold at least PCAP_ERRBUF_SIZE chars.


       pcap_open_offline_with_tstamp_precision() and
       pcap_fopen_offline_with_tstamp_precision() became available in
       libpcap release 1.5.1.  In previous releases, time stamps from a
       savefile are always given in seconds and microseconds.

SEE ALSO         top

       pcap(3PCAP), pcap-savefile(5)

COLOPHON         top

       This page is part of the libpcap (packet capture library)
       project.  Information about the project can be found at 
       ⟨http://www.tcpdump.org/⟩.  If you have a bug report for this
       manual page, see ⟨http://www.tcpdump.org/#patches⟩.  This page
       was obtained from the project's upstream Git repository
       ⟨https://github.com/the-tcpdump-group/libpcap.git⟩ on 2021-08-27.
       (At that time, the date of the most recent commit that was found
       in the repository was 2021-08-17.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

                             23 August 2018     PCAP_OPEN_OFFLINE(3PCAP)