[Rd] Basic Question on error(_(...

[Peter Dalgaard]

statmobile at gmail.com wrote:
> I'm sorry to bother this list with such trivial questions, but I'm
> trying to take Prof. Ripley's advice in porting some Lapack wrappers
> into my own code, because they are not public.  I'm specifically
> choosing programs from R-2.5.0/src/modules/lapack/Lapack.c.  
>
> I can't seem to understand the context in functions such as:
>
> <snip>
>         error(_("the leading minor of order %d is not positive
>         definite"),
>               i);
> </snip> 
>
> in functions such as modLa_chol.  Is there some place I can look to
> understand the usage of the underscore '_', or could someone explain
> this to me?
>   
This has to do with internationalization. It signifies that translations 
are available for the error message, e.g. the file "de.po" in the R 
sources has

#: src/modules/lapack/Lapack.c:629
#, c-format
msgid "the leading minor of order %d is not positive definite"
msgstr "der führende Minor der Ordnung %d ist nicht positiv definit"