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.TH PCAP_NEXT_EX 3PCAP "5 April 2008"
.SH NAME
pcap_next_ex, pcap_next \- read the next packet from a pcap_t
.SH SYNOPSIS
.nf
.ft B
#include <pcap/pcap.h>
.ft
.LP
.ft B
int pcap_next_ex(pcap_t *p, struct pcap_pkthdr **pkt_header,
.ti +8
const u_char **pkt_data);
const u_char *pcap_next(pcap_t *p, struct pcap_pkthdr *h);
.ft
.fi
.SH DESCRIPTION
.B pcap_next_ex()
reads the next packet and returns a success/failure indication.
If the packet was read without problems, the pointer pointed to by the
.I pkt_header
argument is set to point to the
.I pcap_pkthdr
struct for the packet, and the
pointer pointed to by the
.I pkt_data
argument is set to point to the data in the packet.
.PP
.B pcap_next()
reads the next packet (by calling
.B pcap_dispatch()
with a
.I cnt
of 1) and returns a
.I u_char
pointer to the data in that packet.
The
.I pcap_pkthdr
structure pointed to by
.I h
is filled in with the appropriate values for the packet.
.SH RETURN VALUE
.B pcap_next_ex()
returns 1 if the packet was read without problems, 0
if packets are being read from a live capture, and the timeout expired,
\-1 if an error occurred while reading the packet, and \-2 if
packets are being read from a ``savefile'', and there are no more
packets to read from the savefile.
If \-1 is returned,
.B pcap_geterr()
or
.B pcap_perror()
may be called with
.I p
as an argument to fetch or display the error text.
.PP
.B pcap_next()
returns a pointer to the packet data on success, and returns
.B NULL
if an error occured, or if no packets were read from a live
capture (if, for example, they were discarded because they didn't pass
the packet filter, or if, on platforms that support a read timeout that
starts before any packets arrive, the timeout expires before any packets
arrive, or if the file descriptor for the capture device is in
non-blocking mode and no packets were available to be read), or if no
more packets are available in a ``savefile.''  Unfortunately, there is
no way to determine whether an error occured or not.
.SH SEE ALSO
pcap(3PCAP), pcap_geterr(3PCAP), pcap_dispatch(3PCAP)