pcap_setnonblock(3PCAP) man page
This man page documents libpcap version 1.11.0-PRE-GIT (see also: 1.10.4, 1.10.2, 1.10.1, 1.10.0, 1.9.1, 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
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_ERRBUF_SIZE
chars.
In ``non-blocking'' mode, an attempt to read from the capture descriptor with pcap_dispatch(3PCAP) and pcap_next_ex(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)
will loop forever, consuming CPU time when no packets are currently
available;
pcap_dispatch()
should be used instead.
pcap_next(3PCAP)
will return
NULL
if there are no packets currently available to read;
this is indistinguishable from an error, so
pcap_next_ex()
should be used instead.
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_setnonblock()
return 0 on success,
PCAP_ERROR_NOT_ACTIVATED
if called on a capture handle that has been created but not activated,
and
PCAP_ERROR
for other errors.
pcap_getnonblock()
returns the current ``non-blocking'' state of the capture descriptor on
success; it always returns
0
on ``savefiles''.
It returns
PCAP_ERROR_NOT_ACTIVATED
if called on a capture handle that has been created but not activated,
and
PCAP_ERROR
for other errors.
If
PCAP_ERROR
is returned,
errbuf
is filled in with an appropriate error message.