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.TH PCAP_DUMP_OPEN 3PCAP "5 April 2008"
.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_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 "-" in a synonym
for
.BR stdout .
.PP
.B pcap_dump_fopen()
is called to write data to an existing open stream
.IR fp .
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()
and activated by an earlier call to
.BR pcap_activate() ,
or returned by an earlier call to
.BR pcap_open_offline() ,
.BR pcap_open_live() ,
or
.BR pcap_open_dead() .
The link-layer type and snapshot length from
.I p
are used as the link-layer type and snapshot length of the output file.
.SH RETURN VALUES
A pointer to a
.B pcap_dumper_t
structure to use in subsequent
.B pcap_dump()
and
.B pcap_dump_close()
calls is returned on success.
.B NULL
is returned on failure.
If
.B NULL
is returned,
.B pcap_geterr(\fIp\fB)
can be used to get the error text.
.SH SEE ALSO
pcap(3PCAP), pcap_create(3PCAP), pcap_activate(3PCAP),
pcap_open_offline(3PCAP), pcap_open_live(3PCAP), pcap_open_dead(3PCAP),
pcap_dump(3PCAP), pcap_dump_close(3PCAP), pcap_geterr(3PCAP),
pcap-savefile(5)