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(3pcap)
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>
struct timeval *pcap_get_required_select_timeout(pcap_t *p);
DESCRIPTION
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(2), poll(2), epoll_wait(2), and kevent() calls if
pcap_get_selectable_fd(3PCAP) returns PCAP_ERROR.
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 PCAP_ERROR must
be put in non-blocking mode with pcap_setnonblock(3PCAP), 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(3PCAP) or pcap_next_ex(3PCAP)
will return 0 in this case, but will not block.
pcap_get_required_select_timeout() is not available on Windows.
RETURN VALUE
A pointer to a struct timeval is returned if the timeout is required;
otherwise NULL is returned.
BACKWARD COMPATIBILITY
This function became available in libpcap release 1.9.0. In previous
releases, select(), poll(), epoll_wait(), and kevent() cannot be used
on any capture source for which pcap_get_selectable_fd returns -1.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------------+
|Availability | system/library/libpcap |
+---------------+------------------------+
|Stability | Uncommitted |
+---------------+------------------------+
SEE ALSO
pcap(3PCAP), pcap_get_selectable_fd(3PCAP), select(2), poll(2),
epoll_wait(2), kqueue(2)
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from https://www.tcpdump.org/release/libp-
cap-1.9.1.tar.gz.
Further information about this software can be found on the open source
community website at https://www.tcpdump.org/.
25 July 2018
PCAP_GET_REQUIRED_SELECT_TIMEOUT(3pcap)