---
name: "gencmn"
section: "8"
platform: "linux"
package: "icu"
version: "78.3-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/gencmn"
---

# gencmn(8)

generate an ICU memory-mappable data file

## NAME

**gencmn** - generate an ICU memory-mappable data file

## SYNOPSIS

**gencmn** \[ **-h, -?, --help** \] \[ **-v, --verbose** \] \[ **-c, --copyright** \| **-C, --comment** *comment* \] \[ **-d, --destdir** *destination* \] \[ **-n, --name** *name* \] \[ **-t, --type** *fileext* \] \[ **-S, --source** \] \[ **-e, --entrypoint** *name* \] *maxsize* \[ *listfilename* \]

## DESCRIPTION

**gencmn** takes a set of files and packages them as an ICU memory-mappable data file. The resulting data file can then be used directly by ICU.

**gencmn** reads a list of files to be packaged from either the supplied *listfilename* file, or from its standard output. It packages all the files from the list that are not bigger than *maxsize* bytes, except if *maxsize* is 0, which indicates that there is no size limit on files.

## OPTIONS

- **-h, -?, --help**

  Print help about usage and exit.

- **-v, --verbose**

  Display extra informative messages during execution.

- **-c,****--copyright**

  Include the ICU copyright notice in the resulting data.

- **-C, --comment** *comment*

  Include the specified *comment* in the resulting data instead of the ICU copyright notice.

- **-d, --destdir** *destination*

  Set the destination directory to *destination*. The default destination directory is specified by the environment variable **ICU\_DATA**.

- **-n, --name** *name*

  Set the data name to *name* instead of the default. This name is also used as the base name of the output. The default name is made of the *icudt* prefix, followed by a two-digit version number corresponding to the current version of the ICU release, and a single letter indicating the endianness of the data (the letter *b* indicated big endian data, and the letter *l* indicates little endian ones).

- **-t, --type** *type*

  Use *type* as the type of the data. This type is also used as the extension of the generated data file. The default type ie *dat*.

- **-S, --source**

  Write a C source file with the table of contents of the data.

- **-e, --entrypoint** *name*

  Set the data entry point (used for linking against the data in a shared library form) to *name*. The default entry point name is made of the data (set by the **-n, --name** option) followed by an underscore and the type of the data (set by the **-t, --type** option).

## ENVIRONMENT

- **ICU\_DATA**

  Specifies the directory containing ICU data. Defaults to **${prefix}/share/icu/78.3/**. Some tools in ICU depend on the presence of the trailing slash. It is thus important to make sure that it is present if **ICU\_DATA** is set.

## VERSION

78\.3

## COPYRIGHT

Copyright (C) 2000-2001 IBM, Inc. and others.

## SEE ALSO

[**decmn**(8)](/decmn/8.md)