pcap_setnonblock(3) 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];
pcap_setnonblock(3) *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''. errbuf is a buffer large enough to hold at least
PCAP_ERRBUF_SIZE chars.
In ``non-blocking'' mode, an attempt to read from the capture
descriptor with pcap_dispatch(3) and pcap_next_ex(3) will, if
no packets are currently available to be read, return 0 immediately
rather than blocking waiting for packets to arrive.
pcap_loop(3) will loop forever, consuming CPU time when no packets
are currently available; pcap_dispatch() should be used instead.
pcap_next(3) 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(3) or opened with
pcap_open_live(3), 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(3) 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.
SEE ALSO
pcap(3), pcap_next_ex(3), pcap_geterr(3)
30 November 2023 pcap_setnonblock(3)
libpcap 1.10.5 - Generated Sat Aug 31 09:17:54 CDT 2024