---
name: "pcap_dump_ftell"
section: "3pcap"
platform: "linux"
package: "libpcap"
version: "1.11.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/pcap_dump_ftell/3pcap"
---

# pcap\_dump\_ftell(3pcap)

get the current file offset for a savefile being written

## NAME

pcap\_dump\_ftell, pcap\_dump\_ftell64 - get the current file offset for a savefile being written

## SYNOPSIS

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

**long pcap\_dump\_ftell(pcap\_dumper\_t \*p);** **int64\_t pcap\_dump\_ftell64(pcap\_dumper\_t \*p);**

## DESCRIPTION

**pcap\_dump\_ftell**() **returns the current file position for the \`\`savefile'', representing the** **number of bytes written by** **pcap\_dump\_open**(3PCAP) **and** **pcap\_dump**(3PCAP). **PCAP\_ERROR** **is returned on error.  If the current file position does not fit in a** **long**, **it will be truncated; this can happen on 32-bit UNIX-like systems with** **large file support and on Windows.** **pcap\_dump\_ftell64**() **returns the current file position in a** **int64\_t**, **so if file offsets that don't fit in a** **long** **but that fit in a** **int64\_t** **are supported, this will return the file offset without truncation.** **PCAP\_ERROR** **is returned on error.**

## BACKWARD COMPATIBILITY

**The function** **pcap\_dump\_ftell64**() **became available in libpcap release 1.9.0.  In previous releases, there** **was no mechanism to obtain a file offset that is too large to fit in a** **long**.

## SEE ALSO

**pcap**(3PCAP)