x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
PCAP_SETNONBLOCK(3PCAP) PCAP_SETNONBLOCK(3PCAP)
NAME
pcap_setnonblock, pcap_getnonblock - set or get the state of non-block-
ing 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 non-
block 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 descrip-
tor with pcap_dispatch(3PCAP) and pcap_next_ex(3PCAP) will, if no pack-
ets 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; pacp_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_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 appro-
priate error message.
errbuf is assumed to be able to hold at least PCAP_ERRBUF_SIZE chars.
SEE ALSO
pcap(3PCAP), pcap_next_ex(3PCAP), pcap_geterr(3PCAP)
25 July 2018 PCAP_SETNONBLOCK(3PCAP)
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