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pcap_activate - activate a capture handle
int pcap_activate(pcap_t *p);
pcap_activate() is used to activate a packet capture handle to look at
packets on the network, with the options that were set on the handle
being in effect.
pcap_activate() returns 0 on success without warnings, a non-zero posi-
tive value on success with warnings, and a negative value on error. A
non-zero return value indicates what warning or error condition
The possible warning values are:
Promiscuous mode was requested, but the capture source doesn't
support promiscuous mode.
The time stamp type specified in a previous
pcap_set_tstamp_type() call isn't supported by the capture
source (the time stamp type is left as the default),
Another warning condition occurred; pcap_geterr() or pcap_per-
ror() may be called with p as an argument to fetch or display a
message describing the warning condition.
The possible error values are:
The handle has already been activated.
The capture source specified when the handle was created doesn't
The process doesn't have permission to open the capture source.
The process has permission to open the capture source but
doesn't have permission to put it into promiscuous mode.
Monitor mode was specified but the capture source doesn't sup-
port monitor mode.
The capture source device is not up.
Another error occurred. pcap_geterr() or pcap_perror() may be
called with p as an argument to fetch or display a message
describing the error.
If PCAP_WARNING_PROMISC_NOTSUP, PCAP_ERROR_NO_SUCH_DEVICE, or
PCAP_ERROR_PERM_DENIED is returned, pcap_geterr() or pcap_perror() may
be called with p as an argument to fetch or display an message giving
additional details about the problem that might be useful for debugging
the problem if it's unexpected.
Additional warning and error codes may be added in the future; a pro-
gram should check for positive, negative, and zero return codes, and
treat all positive return codes as warnings and all negative return
codes as errors. pcap_statustostr() can be called, with a warning or
error code as an argument, to fetch a message describing the warning or
7 April 2014 PCAP_ACTIVATE(3)