pcap_setnonblock(3PCAP) man page
Updated: 25 July 2018 •
View in plain text •
Return to Main Contents
This man page documents libpcap version 1.9.1 (see also: git master branch, 1.10.4, 1.10.2, 1.10.1, 1.10.0, 1.8.1, 1.7.4, 1.6.2, 1.5.3).
Your system may have a different version installed, possibly with some local modifications. To achieve the best results, please make sure this version of this man page suits your needs. If necessary, try to look for a different version on this web site or in the man pages available in your installation.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,
PCAP_ERROR
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(3PCAP)
will, if no packets are currently available to be read, return 0
immediately rather than blocking waiting for packets to arrive.
pcap_loop(3PCAP)
and
pcap_next(3PCAP)
will not work in ``non-blocking'' mode.
When first activated with pcap_activate(3PCAP) or opened with pcap_open_live(3PCAP) , a capture handle is not in ``non-blocking mode''; a call to pcap_setnonblock() is required in order to put it into ``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,
PCAP_ERROR
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
COLOPHON
This HTML man page was generated at 10:40:22 GMT, October 05, 2021
from a source man page in "The Tcpdump Group" git repositories
using man2html and other tools.