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Libwandio is a software library written in C that provides an API for transparently reading from and writing to files using a variety of supported compression methods. Provided pthreads are available, I/O performance will be improved by doing any compression and/or decompression using a separate thread.

Libwandio supports the following compression methods, as long as the development libraries are installed on your machine at compile time:

  • zlib
  • bzip2
  • lzo (write-only)
  • lzma
  • lz4
  • zstd
  • http (read-only)

Previously libwandio was bundled with libtrace, as it was an integral part of how libtrace read and wrote packet trace files. However, libwandio also has applications outside of packet traces so it has been decoupled from libtrace so that it may be used separately. If you have installed a recent version of libtrace 3 (3.0.15 or later), you probably already have libwandio installed.

Starting from libtrace 4, libwandio will no longer be included with libtrace and must be installed separately for libtrace to build and run.

The latest version is 4.2.3 -- Released on 2020/05/18.

The wandio wiki is a good source of (hopefully up-to-date) information on how to install and use libwandio.

We also maintain our own packages for Debian and Ubuntu (starting from version 1.0.4). Packages can be obtained from here.

NEW: From libwandio 1.0.4 onwards, the libwandio source code is licensed under the LGPL v3.

All releases of libwandio prior to 1.0.4 are licensed under the GPL v2.


We are very interested in hearing feedback on libwandio. If you have any requests or comments, or wish to report a bug, please email contact@wand.net.nz.