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# Using profiling to aid direction setting

In computer programming the term profiling is used to indicate when a program is analysed to see where it spends most of its time. The theory being that that is where you should put in effort to optimise the code and thus improve speed and responsiveness.

A similar concept can be applied to translation. If you translate only the messages that people actually see then you can optimise the effort that you expend on translation.

It also helps focus the translation effort onto programs that are actually being used, not those that you guess might be being used.

## How profiling works on Linux

The gettext libraries are called by a program with a request for the translation of a given string. Gettext looks up the string and returns the translation to the program.

When profiling this call to gettext is intercepted and the message requested is output to a file. This file is then later processed and contains all strings that should be translated.

## Problems with profiling

- Many UI design tools and newer UI code calls all strings when initialising the UI. That means that you see many messages that in fact were never seen by the user.
- Spurious files. Many GUI program call command line tools to retrieve data. When the command line tool is called those messages are logged but were never seen by the user.
- Profiling depends on the usage profile of the user. An end-user and a system administrator will use different tools. To work best you need a group of people using your target applications.

### Solutions

- The UI design tools would require changes to only call strings for windows that are visible. But this would only happen if translators can indicate a strong case for the fact that they use and find profiling effective.
- You can circumvent the calling of spurious command line tools by GUI tools by using:

export LC_ALL=C

## Using profiling

The Gettextlog tool is available here:

`http://sourceforge.net/projects/gettextlog/`

An RPM is also available:

`http://prdownloads.sourceforge.net/gettextlog/gettextlog-0.6-1.i386.rpm?download`

Once installed...

    export LD_PRELOAD=/file/to/gettextlog.so

You can place this in your `.bash_profile` to log continuously or in `/etc/profile.d/` add a `gettextlog.sh` script to initialise LD_PRELOAD

You can run it against individual programs with the `run-with-gettextlog` program

Your profiles will be output to:

    $HOME/gettextlog/$PROGRAM.po