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.TH PCAP_DUMP_OPEN 3PCAP "22 August 2018"

.SH NAME

pcap_dump_open, pcap_dump_fopen \- open a file to which to write packets

.SH SYNOPSIS

.nf

.ft B

#include <pcap/pcap.h>

.ft

.nf

.LP

.ft B

pcap_dumper_t *pcap_dump_open(pcap_t *p, const char *fname);

pcap_dumper_t *pcap_dump_open_append(pcap_t *p, const char *fname);

pcap_dumper_t *pcap_dump_fopen(pcap_t *p, FILE *fp);

.ft

.fi

.SH DESCRIPTION

.B pcap_dump_open()

is called to open a ``savefile'' for writing.

.I fname

specifies the name of the file to open. The file will have

the same format as those used by

.BR tcpdump (1)

and

.BR tcpslice (1).

The name "-" is a synonym

for

.BR stdout .

.PP

.B pcap_dump_fopen()

is called to write data to an existing open stream

.IR fp ;

this stream will be closed by a subsequent call to

.BR pcap_dump_close(3PCAP) .

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

.PP

.I p

is a capture or ``savefile'' handle returned by an earlier call to

.B pcap_create(3PCAP)

and activated by an earlier call to

.BR \%pcap_activate(3PCAP) ,

or returned by an earlier call to

.BR \%pcap_open_offline(3PCAP) ,

.BR pcap_open_live(3PCAP) ,

or

.BR pcap_open_dead(3PCAP) .

The time stamp precision, link-layer type, and snapshot length from

.I p

are used as the link-layer type and snapshot length of the output file.

.PP

.B pcap_dump_open_append()

is like

.B pcap_dump_open()

but does not create the file if it does not exist and, if it does

already exist, and is a pcap file with the same byte order as the host

opening the file, and has the same time stamp precision, link-layer

header type, and snapshot length as

.IR p ,

it will write new packets at the end of the file.

.SH RETURN VALUES

A pointer to a

.B pcap_dumper_t

structure to use in subsequent

.B pcap_dump(3PCAP)

and

.B pcap_dump_close(3PCAP)

calls is returned on success.

.B NULL

is returned on failure.

If

.B NULL

is returned,

.B pcap_geterr(3PCAP)

can be used to get the error text.

.SH BACKWARD COMPATIBILITY

.PP

The

.B pcap_dump_open_append()

function became available in libpcap release 1.7.2.  In previous

releases, there is no support for appending packets to an existing

savefile.

.SH SEE ALSO

pcap(3PCAP),

\%pcap-savefile(@MAN_FILE_FORMATS@)