pcap_dump_open(3pcap) — Linux manual page
PCAP_DUMP_OPEN(3PCAP) PCAP_DUMP_OPEN(3PCAP)
NAME
pcap_dump_open, pcap_dump_open_append, pcap_dump_fopen - open a
file to which to write packets
SYNOPSIS
#include <pcap/pcap.h>
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);
DESCRIPTION
pcap_dump_open() is called to open a ``savefile'' for writing.
fname specifies the name of the file to open. The file will have
the same format as those used by tcpdump(1) and tcpslice(1). If
the file does not exist, it will be created; if the file exists,
it will be truncated and overwritten. The name "-" is a synonym
for stdout.
pcap_dump_fopen() is called to write data to an existing open
stream fp; this stream will be closed by a subsequent call to
pcap_dump_close(3PCAP). The stream is assumed to be at the
beginning of a file that has been newly created or truncated, so
that writes will start at the beginning of the file. Note that
on Windows, that stream should be opened in binary mode.
p is a capture or ``savefile'' handle returned by an earlier call
to pcap_create(3PCAP) and activated by an earlier call to
pcap_activate(3PCAP), or returned by an earlier call to
pcap_open_offline(3PCAP), pcap_open_live(3PCAP), or
pcap_open_dead(3PCAP). The time stamp precision, link-layer
type, and snapshot length from p are used as the link-layer type
and snapshot length of the output file.
pcap_dump_open_append() is like pcap_dump_open() but, if the file
already exists, 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 p, it will write
new packets at the end of the file.
RETURN VALUE
A pointer to a pcap_dumper_t structure to use in subsequent
pcap_dump(3PCAP) and pcap_dump_close(3PCAP) calls is returned on
success. NULL is returned on failure. If NULL is returned,
pcap_geterr(3PCAP) can be used to get the error text.
BACKWARD COMPATIBILITY
The 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.
SEE ALSO
pcap(3PCAP), pcap-savefile(5)
COLOPHON
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 2024-06-14.
(At that time, the date of the most recent commit that was found
in the repository was 2024-06-04.) 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
man-pages@man7.org