What does printf (_("hello, world\n")) mean? [duplicate]

This question already has answers here: 开发者_C百科 Underscore `_` before the format string (3 answers) Closed 3 years ago.

What's the role of the _("hello, world\n") argument to printf/puts etc ? I often find it while reading GNU source code.

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See GNU Gettext -- it (_(...)) is used as a "binding site" for translation.

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This is the gettext internationalization system.

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it is a macro that replaces the gettext translation function. For a thorough explanation on gettext, check out this write-up: http://oriya.sarovar.org/docs/gettext_single.html

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The underscore function (or macro) is a custom function defined by whatever project you're looking at. By convention, it's defined to send the string to GNU Gettext to fetch a translated version of the string for the user's current language.

This use of the _ macro is documented in the overview found in the GNU Gettext manual.