pcap_compile (3)

Leading comments

 Copyright (c) 1994, 1996, 1997
	The Regents of the University of California.  All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that: (1) source code distributions
 retain the above copyright notice and this paragraph in its entirety, (2)
 distributions including binary code include the above copyright notice and
 this paragraph in its entirety in the documentation or other materials
 provided with the distribution...

(The comments found at the beginning of the groff file "man3/pcap_compile.3pcap".)

NAME

pcap_compile - compile a filter expression

SYNOPSIS

#include <pcap/pcap.h>

int pcap_compile(pcap_t *p, struct bpf_program *fp,


        const char *str, int optimize, bpf_u_int32 netmask);

DESCRIPTION

pcap_compile() is used to compile the string str into a filter program. See pcap-filter(7) for the syntax of that string. program is a pointer to a bpf_program struct and is filled in by pcap_compile(). optimize controls whether optimization on the resulting code is performed. netmask specifies the IPv4 netmask of the network on which packets are being captured; it is used only when checking for IPv4 broadcast addresses in the filter program. If the netmask of the network on which packets are being captured isn't known to the program, or if packets are being captured on the Linux "any" pseudo-interface that can capture on more than one network, a value of PCAP_NETMASK_UNKNOWN can be supplied; tests for IPv4 broadcast addresses will fail to compile, but all other tests in the filter program will be OK.

RETURN VALUE

pcap_compile() returns 0 on success and -1 on failure. If -1 is returned, pcap_geterr() or pcap_perror() may be called with p as an argument to fetch or display the error text.

SEE ALSO

pcap(3PCAP), pcap_setfilter(3PCAP), pcap_freecode(3PCAP), pcap_geterr(3PCAP), pcap-filter(7)