PCAP_SET_IMMEDIATE_MODE(3PCAP) PCAP_SET_IMMEDIATE_MODE(3PCAP)

NAME

pcap_set_immediate_mode - set immediate mode for a not-yet-activated
capture handle

SYNOPSIS

#include <pcap/pcap.h>

int pcap_set_immediate_mode(pcap_t *p, int immediate_mode);

DESCRIPTION

pcap_set_immediate_mode() sets whether immediate mode should be set
on a capture handle when the handle is activated. In immediate mode,
packets are always delivered as soon as they arrive, with no
buffering. If immediate_mode is non-zero, immediate mode will be
set, otherwise it will not be set.

RETURN VALUE

pcap_set_immediate_mode() returns 0 on success or
PCAP_ERROR_ACTIVATED if called on a capture handle that has been
activated.

BACKWARD COMPATIBILITY

This function became available in libpcap release 1.5.0. In previous
releases, if immediate delivery of packets is required:

on FreeBSD, NetBSD, OpenBSD, DragonFly BSD, macOS, and Solaris
11, immediate mode must be turned on with a BIOCIMMEDIATE
ioctl(2), as documented in bpf(7D), on the descriptor returned
by pcap_fileno(3PCAP), after pcap_activate(3PCAP) is called;

on Solaris 10 and earlier versions of Solaris, immediate mode
must be turned on by using a read timeout of 0 when opening
the device (this will not provide immediate delivery of
packets on other platforms, so don't assume it's sufficient);

on Digital UNIX/Tru64 UNIX, immediate mode must be turned on
by doing a BIOCMBIC ioctl(), as documented in packetfilter(7),
to clear the ENBATCH flag on the descriptor returned by
pcap_fileno(3PCAP), after pcap_activate(3PCAP) is called;

on Windows, immediate mode must be turned on by calling
pcap_setmintocopy() with a size of 0.

On Linux, with previous releases of libpcap, capture devices are
always in immediate mode; however, in 1.5.0 and later, they are, by
default, not in immediate mode, so if pcap_set_immediate_mode() is
available, it should be used.

On other platforms, capture devices are always in immediate mode.

SEE ALSO

pcap(3PCAP), pcap_create(3PCAP), pcap_activate(3PCAP)

23 August 2018 PCAP_SET_IMMEDIATE_MODE(3PCAP)