freebsd man page for pcap_setdirection

PCAP_SETDIRECTION(3)					     Library Functions Manual					      PCAP_SETDIRECTION(3)

NAME
       pcap_setdirection - set the direction for which packets will be captured

SYNOPSIS
       #include <pcap/pcap.h>

       int pcap_setdirection(pcap_t *p, pcap_direction_t d);

DESCRIPTION
       pcap_setdirection()  is	used  to  specify  a  direction that packets will be captured.	d is one of the constants PCAP_D_IN, PCAP_D_OUT or
       PCAP_D_INOUT.  PCAP_D_IN will only capture packets received by the device, PCAP_D_OUT will only capture packets	sent  by  the  device  and
       PCAP_D_INOUT will capture packets received by or sent by the device.  PCAP_D_INOUT is the default setting if this function is not called.

       pcap_setdirection() isn't necessarily fully supported on all platforms; some platforms might return an error for all values, and some other
       platforms might not support PCAP_D_OUT.

       This operation is not supported if a ``savefile'' is being read.

RETURN VALUE
       pcap_setdirection() returns 0 on success and -1 on failure.  If -1 is returned, pcap_geterr() or pcap_perror() may be called with p  as	an
       argument to fetch or display the error text.

SEE ALSO
       pcap(3), pcap_geterr(3)

								   5 April 2008 					      PCAP_SETDIRECTION(3)