---
name: "pcap_offline_filter"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/pcap_offline_filter"
---

# pcap\_offline\_filter(3)

check whether a filter matches a packet

## NAME

pcap\_offline\_filter - check whether a filter matches a packet

## SYNOPSIS

```
#include <pcap/pcap.h>
```

**int pcap\_offline\_filter(const struct bpf\_program \*fp,**\
     **const struct pcap\_pkthdr \*h, const u\_char \*pkt);**

## DESCRIPTION

**pcap\_offline\_filter**() checks whether a filter matches a packet. *fp* is a pointer to a *bpf\_program* struct, usually the result of a call to [**pcap\_compile**(3)](/pcap_compile/3.md). *h* points to the *pcap\_pkthdr* structure for the packet, and *pkt* points to the data in the packet.

## RETURN VALUE

**pcap\_offline\_filter**() returns the return value of the filter program.  This will be zero if the packet doesn't match the filter and non-zero if the packet matches the filter.

## SEE ALSO

[**pcap**(3)](/pcap/3.md)