How to inform Free Pascal Compiler to set Locale ID for the compiled application

Question

In Delphi there is an option VersionInfo->Language->Locale ID when viewing project properties.
I was wandering how to set such property for a program being compiled under Free Pascal.
Any solution is welcome: command line argument or preprocessor directive such as {$key value}; equivalent to Delphi.

Answer 1

If you can build your projects using *.lpi files then I would try to add the following into your project's Project.lpi file. In the following snippet is shown how to set the project's locale ID (for Windows platform) to 0405 (Czech).

<?xml version="1.0"?>
<CONFIG>
  <ProjectOptions>
    ...
    <VersionInfo>
      <UseVersionInfo Value="True"/>
      <Language Value="0405"/>
      <StringTable ProductVersion=""/>
    </VersionInfo>
    ...
  </ProjectOptions>
  ...
</CONFIG>

Or if you are using Lazarus IDE then you might use to Delphi very similar settings tab which you can open from Project / Project Options ... and as in Delphi go to Version Info where is the Language selection combo box available if you include the version info into the project.

Answer 2

Not 100% sure this will work, feel free to vote me down if this doesn't work.

Lazarus will inherit the locale settings it starts with.
You can set the locale info prior to starting Lazarus in Linux/OS X using the command line:

export LC_CTYPE="pt_BR"
export LANG="pt_BR"
export LANGUAGE="pt_BR"
./lazarus

Your compiled application should inherit these settings.

The answer is inspired by this workaround to an error has since been fixed.

I recommend you have a look at the fpc forum as well and ask the question there.
Don't forget it include details like the platform (Linux/Windows/OS X) and the exact version of FPC and Lazarus you are using as well as the actual Locale that you want.

Better answer
From: http://forum.lazarus.freepascal.org/index.php/topic,5924.0.html

Finally, I managed to find a simple and effective way to make my application localizeable. It uses just one unit and no code.
1. Add unit "defaulttranslator" to your uses list.
2. Enable "i18n" in "Project Options" and set "PO output directory" to "locale" or "languages". You can put translation files right into application folder, but that would just make a mess. Don't forget to create an appropriate folder.
3. Add components to the form. If you already have all components on your form, you'll have to move it a little bit, so it's modified.
4. Save your project.
5. Now there should be .po files in your "locale" or "languages" folder. For different languages files should be copied and renamed like so "project1.XX.po", where XX is language code (e.g. "en", "de", etc.).
6. Translate .po files with translation software, and generate .mo files. I suggest to use POEdit.
7. Run your application, and the translation to be used will be chosen by your regional locale settings. If you need to test other language - just start your application with following command line parameters - "-l XX" or "-lang XX", where XX is a language code.
This method is not very versatile, but it translates resource strings and LCL component properties.