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(4), 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)