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)