freebsd man page for pcap_setnonblock

PCAP_SETNONBLOCK(3)					     Library Functions Manual					       PCAP_SETNONBLOCK(3)

NAME
       pcap_setnonblock, pcap_getnonblock - set or get the state of non-blocking mode on a capture device

SYNOPSIS
       #include <pcap/pcap.h>

       char errbuf[PCAP_ERRBUF_SIZE];

       int pcap_setnonblock(pcap_t *p, int nonblock, char *errbuf);
       int pcap_getnonblock(pcap_t *p, char *errbuf);

DESCRIPTION
       pcap_setnonblock()  puts  a  capture  handle into ``non-blocking'' mode, or takes it out of ``non-blocking'' mode, depending on whether the
       nonblock argument is non-zero or zero.  It has no effect on ``savefiles''.  If there is an error, -1 is returned and errbuf  is	filled	in
       with an appropriate error message; otherwise, 0 is returned.  In ``non-blocking'' mode, an attempt to read from the capture descriptor with
       pcap_dispatch() will, if no packets are currently available to be read, return 0 immediately rather than blocking waiting  for  packets	to
       arrive.	pcap_loop() and pcap_next() will not work in ``non-blocking'' mode.

RETURN VALUE
       pcap_getnonblock() returns the current ``non-blocking'' state of the capture descriptor; it always returns 0 on ``savefiles''.  If there is
       an error, -1 is returned and errbuf is filled in with an appropriate error message.

       errbuf is assumed to be able to hold at least PCAP_ERRBUF_SIZE chars.

SEE ALSO
       pcap(3), pcap_loop(3), pcap_next_ex(3), pcap_geterr(3)

								   5 April 2008 					       PCAP_SETNONBLOCK(3)