Tip 1: Call the setlocale()
function to set language (locale) at the beginning of programs.
Call setlocale() for non-Xt/Motif based programs. Because it affects
locale sensitive functions, setlocale() should usually be called at
the beginning of programs. But it can be called whenever necessary.
Call
XtSetLanguageProc() for Xt/Motif based programs.
XtSetLanguageProc() should be called before Xt initialization. It does
not actually set a locale, but rather registers a default language procedure
which contains a setlocale() function call. Because Xt only calls the
procedure registered in XtSetLanguageProc() when Xt is initialized,
any XtSetLanguageProc() function calls after Xt initialization have no
effect.
Tip 2: Do not hard-code messages, labels, font names or widget layout values.
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Get messages from the message catalogs for non-X based programs. Use the
catgets() function.
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Get messages, labels, font names and layout values from resource files
(or message catalog files) for X based programs. You can also define your
own resources and use them.
Tip 3: Use a font set or a font list instead of a font.
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Some Asian languages need several fonts. The fonts should be handled as
font sets or a font lists.
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If you use Xlib functions and need to create a font set in your program,
use XCreateFontSet(), instead of XLoadQueryFont().
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If you use Motif functions and need to create a font list in your program,
use functions such as XmFontListEntryLoad(), XmFontListEntryCreate()
and XmFontListAppendEntry().
Tip 4: Do not use special characters for widget names with Xt/Motif programs.
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All widgets should have names because the use of NULL as a widget
name makes it impossible to identify widgets for localization. Widget names
should contain only ASCII alphanumeric characters and underscore; it is
difficult or impossible to localize strings if a widget name contains whitespace,
punctuation or special characters such as '*', '.', ':'
and '?'.
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One common practice causes particular problems: naming a widget using its
label string often leads to widget names that are difficult to use, because
labels sometimes contain the aforementioned special characters.
Tip 5: Do not fix widget arrangements and sizes.
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The length of strings or labels may change depending on languages. Do not
fix a layout or sizes of widgets just for English.
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A widget layout should be able to change automatically based on a language
(locale). If this practice is difficult to implement, you should define
widget sizes and spacings/locations in the resource files.
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Because font width varies among languages, the number of columns and the
size of a text (field) widget vary. Therefore, the layout with text (field)
widgets should be adjusted automatically based on the current language,
or changed by values in a resource file. They should not be hard-coded.
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Using a form widget is one relatively easy (and recommended) method to
automatically adjust the layout of primitive widgets. Define values for
ATTACH_* resources explicitly and correctly.
Tip 6: Use multi-byte functions for X based programs.
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Use XmbDrawString() instead of XDrawString() to draw
texts.
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Use XmbLookupString() instead of XLookupString() in cases
when the program handles X events directly.
Tip 7: Use multi-byte or wide character functions for text processing.
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Do not assume characters are the ASCII code set. Some code sets use 8 bits
for a character, and others may use multi-byte characters which have several
bytes per character.
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Use multi-byte or wide character functions for text processing, such as
mblen(),mbtowc(),
mbstowcs(), iswupper(), and isideogram().
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In some languages, there are no spaces between words. This affects algorithms
for word wrapping.
Tip 8: Use Selection for Cut & Paste with X based programs.
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Use Selection instead of Cut Buffer for Cut & Paste.
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Use compound texts for inter-client communications.
Tip 9: Use LC_MESSAGES to get messages.
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Be sure to use the LC_MESSAGES sub-category of a locale when deciding
where to get message catalogs, HTML files, etc. Do not use the LANG
environment
variable directly and do not use LC_ALL for querying.
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When calling catopen(), specify the OFLAG of NL_CAT_LOCALE.
Tip 10: Use the XPG4 message catalog functions instead of gettxt().
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Use the XPG4 message catalog functions such as catopen() and
catgets() instead of the outdated interface: gettxt(). You may still
use the gettxt command in shell scripts.
