установить или получить состояние неблокирующего режима на устройстве захвата (set or get the state of non-blocking mode on a capture device)
Имя (Name)
pcap_setnonblock, pcap_getnonblock - set or get the state of non-
blocking mode on a capture device
Синопсис (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);
Описание (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) 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; 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.
Возвращаемое значение (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.
Смотри также (See also)
pcap(3PCAP), pcap_next_ex(3PCAP), pcap_geterr(3PCAP)
