pcap_freecode.3pcap man page
pcap_freecode — free a BPF program
#include <pcap/pcap.h> void pcap_freecode(struct bpf_program *);
pcap_freecode() is used to free up allocated memory pointed to by a bpf_program struct generated by pcap_compile() when that BPF program is no longer needed, for example after it has been made the filter program for a pcap structure by a call to pcap_setfilter().
pcap(3PCAP), pcap_compile(3PCAP), pcap_setfilter(3PCAP)