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 VALUES

       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)

                                                   3 July 2020                             PCAP_DUMP_OPEN(3PCAP)