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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

#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
 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 (@MAN_FILE_FORMATS@), 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
 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.
 BACKWARD COMPATIBILITY
 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
pcap(3PCAP), pcap-savefile(@MAN_FILE_FORMATS@)