#include <pcap/pcap.h> int pcap_set_timeout(pcap_t *p, int to_ms);
pcap_set_timeout() sets the packet buffer timeout that will be used on a capture handle when the handle is activated to to_ms, which is in units of milliseconds. (See pcap(3PCAP) for an explanation of the packet buffer timeout.)
The behavior, if the timeout isn't specified, is undefined, as is the behavior if the timeout is set to zero or to a negative value. We recommend always setting the timeout to a non-zero value unless immediate mode is set, in which case the timeout has no effect.
pcap_set_timeout() returns 0 on success or PCAP_ERROR_ACTIVATED if called on a capture handle that has been activated.
pcap_create(3PCAP), pcap_activate(3PCAP), pcap_set_immediate_mode(3PCAP)