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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | COLOPHON |
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PCAP_GET_REQUIRED_SELECT_TIMEOUT(3PCAP)AP_GET_REQUIRED_SELECT_TIMEOUT(3PCAP)
pcap_get_required_select_timeout - get a file descriptor on which a
select() can be done for a live capture
#include <pcap/pcap.h>
struct timeval *pcap_get_required_select_timeout(pcap_t *p);
pcap_get_required_select_timeout() 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_timeout() 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
timeout 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() is not available on Windows.
A pointer to a struct timeval is returned if the timeout is required;
otherwise NULL is returned.
pcap(3PCAP), pcap_get_selectable_fd(3PCAP), select(2), poll(2),
epoll_wait(2), kqueue(2)
This page is part of the libpcap (packet capture library) project.
Information about the project can be found at
⟨http://www.tcpdump.org/⟩. If you have a bug report for this manual
page, see ⟨http://www.tcpdump.org/#patches⟩. This page was obtained
from the project's upstream Git repository
⟨https://github.com/the-tcpdump-group/libpcap.git⟩ on 2018-02-02.
(At that time, the date of the most recent commit that was found in
the repository was 2018-01-31.) If you discover any rendering prob‐
lems in this HTML version of the page, or you believe there is a bet‐
ter or more up-to-date source for the page, or you have corrections
or improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to man-pages@man7.org
19 JanuPaCrAyP_2G0E1T8_REQUIRED_SELECT_TIMEOUT(3PCAP)
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