---
name: "tcllib_zlib"
section: "3tcllib"
platform: "linux"
package: "tcllib"
version: "2.0+dfsg-4"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/tcllib_zlib"
---

# tcllib\_zlib(3tcllib)

zlib (de)compression

```

```

## NAME

tcl::transform::zlib - zlib (de)compression

## SYNOPSIS

package require **Tcl 8.6 9**

package require **tcl::transform::core ?1.1?**

package require **tcl::transform::zlib ?1.1?**

**::tcl::transform::zlib** *chan* ?*level*?

```

```

## DESCRIPTION

The **tcl::transform::zlib** package provides a command creating a channel transformation which zlib compresses the written data, and decompresses on reading.

The internal **TclOO** class implementing the transform handler is a sub-class of the **tcl::transform::core** framework.

## API

- **::tcl::transform::zlib** *chan* ?*level*?

  This command creates a zlib compressor transformation on top of the channel *chan* and returns its handle.

  The *level* specifies how much effort is put into the compression, from **0** to **9**, and defaults to **4**.

## BUGS, IDEAS, FEEDBACK

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category *virtchannel* of the *Tcllib Trackers* \[http://core.tcl.tk/tcllib/reportlist\]. Please also report any ideas for enhancements you may have for either package and/or documentation.

When proposing code changes, please provide *unified diffs*, i.e the output of **diff -u**.

Note further that *attachments* are strongly preferred over inlined patches. Attachments can be made by going to the **Edit** form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar.

## KEYWORDS

channel transformation, compression, decompression, reflected channel, tip 230, tip 234, transformation, virtual channel, zlib

## CATEGORY

Channels

## COPYRIGHT

```
Copyright (c) 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>
```