Translations:Development/FAQs/Technical FAQ/39/en

If you do QString translatedStuff = i18n("foobar"); translatedStuff will contain the translation of "foobar", while for const char *markedStuff = I18N_NOOP("foobar"); markedStuff will still contain literal "foobar", but translators will know you want "foobar" translated so you can later on do QString translatedStuff = i18n(markedStuff); and get the translation of "foobar", which wouldn't work without that I18N_NOOP. So, normally you want to just use i18n(), but in cases where you absolutely need to pass something untranslated, but still need to translate it later or in the case that you have something to be translated before the KInstance exists, use I18N_NOOP().