pcap_get_required_select_timeout(3)
NAME
pcap_get_required_select_timeout - get a file descriptor on which a
select() can be done for a live capture
SYNOPSIS
#include <pcap/pcap.h>
pcap_get_required_select_timeout(3) *p);
DESCRIPTION
pcap_get_required_select_timeout(3) returns, on UNIX, a pointer to a
struct timeval containing a value that must be used as the minimum
timeout in select(), poll(), epoll_wait(), and kevent() calls if
pcap_get_selectable_fd() returns -1.
The timeout that should be used in those calls must be no larger than
the smallest of all timeouts returned by pcap_get_required_select_time-
out() for devices from which packets will be captured.
The device for which pcap_get_selectable_fd() returned -1 must be put
in non-blocking mode with pcap_setnonblock(), and an attempt must
always be made to read packets from the device when the select(),
poll(), epoll_wait(), or kevent() call returns.
Note that a device on which a read can be done without blocking may, on
some platforms, not have any packets to read if the packet buffer time-
out has expired. A call to pcap_dispatch() or pcap_next_ex() will
return 0 in this case, but will not block.
pcap_get_required_select_timeout(3) is not available on Windows.
RETURN VALUE
A pointer to a struct timeval is returned if the timeout is required;
otherwise NULL is returned.
SEE ALSO
pcap(3), pcap_get_selectable_fd(3), select(2), poll(2),
epoll_wait(2), kqueue(2)
20 pcap_get_required_select_timeout(3)
libpcap 1.9.0 - Generated Sun Jul 29 14:07:59 CDT 2018