.\" Copyright (c) 1994, 1996, 1997

.\"	The Regents of the University of California.  All rights reserved.

.\"

.\" Redistribution and use in source and binary forms, with or without

.\" modification, are permitted provided that: (1) source code distributions

.\" retain the above copyright notice and this paragraph in its entirety, (2)

.\" distributions including binary code include the above copyright notice and

.\" this paragraph in its entirety in the documentation or other materials

.\" provided with the distribution, and (3) all advertising materials mentioning

.\" features or use of this software display the following acknowledgement:

.\" ``This product includes software developed by the University of California,

.\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of

.\" the University nor the names of its contributors may be used to endorse

.\" or promote products derived from this software without specific prior

.\" written permission.

.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED

.\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF

.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

.\"

.TH PCAP_OPEN_OFFLINE 3PCAP "8 January 2018 "

.SH NAME

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

.SH SYNOPSIS

.nf

.ft B

#include <pcap/pcap.h>

.ft

.LP

.nf

.ft B

char errbuf[PCAP_ERRBUF_SIZE];

.ft

.LP

.ft B

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);

.ft

.fi

.SH DESCRIPTION

.B pcap_open_offline()

and

.B pcap_open_offline_with_tstamp_precision()

are called to open a ``savefile'' for reading.

.PP

.I fname

specifies the name of the file to open. The file can have the pcap file

format as described in

.BR pcap-savefile (@MAN_FILE_FORMATS@),

which is the file format used by, among other programs,

.BR tcpdump (1)

and

.BR tcpslice (1),

or can have the pcapng file format, although not all pcapng files can

be read.

The name "-" is a synonym for

.BR stdin .

.PP

.B pcap_open_offline_with_tstamp_precision()

takes an additional

.I precision

argument specifying the time stamp precision desired;

if

.B PCAP_TSTAMP_PRECISION_MICRO

is specified, packet time stamps will be supplied in seconds and

microseconds,

and if

.B 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.

.PP

Alternatively, you may call

.B pcap_fopen_offline()

or

.B pcap_fopen_offline_with_tstamp_precision()

to read dumped data from an existing open stream

.IR fp .

.B pcap_fopen_offline_with_tstamp_precision()

takes an additional

.I precision

argument as described above.

Note that on Windows, that stream should be opened in binary mode.

.SH RETURN VALUE

.BR pcap_open_offline() ,

.BR pcap_open_offline_with_tstamp_precision() ,

.BR pcap_fopen_offline() ,

and

.B pcap_fopen_offline_with_tstamp_precision()

return a

.I pcap_t *

on success and

.B NULL

on failure.

If

.B NULL

is returned,

.I errbuf

is filled in with an appropriate error message.

.I errbuf

is assumed to be able to hold at least

.B PCAP_ERRBUF_SIZE

chars.

.SH BACKWARD COMPATIBILITY

.B pcap_open_offline_with_tstamp_precision

and

.B 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.

.SH SEE ALSO

pcap(3PCAP), pcap-savefile(@MAN_FILE_FORMATS@)