c - Underscore `_` before the format string

Question

I'm here looking at some C source code and I've found this:

fprintf(stderr, _("Try `%s --help' for more information.
"), command);

I already saw the underscore when I had a look at wxWidget, and I read it's used for internationalization. I found it really horrible (the least intutive name ever), but I tought it's just another weird wxWidget convention.

Now I find it again in some Alsa source. Does anyone know where it comes from?

Answer 1

It comes from GNU gettext, a package designed to ease the internationalization process. The _() function is simply a string wrapper. This function basically replaces the given string on runtime with a translation in the system's language, if available (i.e. if they shipped a .mo file for this language with the program).