R devel - Aug 2019 - --disable-long-double or --enable-long-double=no?

There's a bit of confusion about how to disable long double support in an R
build.

I see --disable-long-double scattered about, e.g.

   - R-exts:
  
https://cran.r-project.org/doc/manuals/r-release/R-exts.html#Writing-portable-packages
   - R-admin:
   https://cran.r-project.org/doc/manuals/r-release/R-admin.html#Solaris
   - CRAN noLD check description:
   https://www.stats.ox.ac.uk/pub/bdr/noLD/README.txt
   - ?capabilities:
   https://stat.ethz.ch/R-manual/R-devel/library/base/html/capabilities.html

However, it's *missing* from ./config (cd r-source && grep
"disable-long-double" configure). Instead there appears to be some
code
built around enable-long-double:

./configure:1808:  --enable-long-double    use long double type [yes]

./configure:24723:# Check whether --enable-long-double was given.

I see the option apparently introduced here in 2012 & the ambiguity is
immediate -- the commit mentions disable-long-double but builds
enable-long-double.

https://github.com/wch/r-source/commit/fb8e36f8be0aaf47a9c54c9effb219dae34f0e41

Could someone please help to clear the confusion?

Thanks
Michael Chirico

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"--disable-long-double" is documented to work and works. 
"--enable-long-double=no" works as well.

Please refer to Autoconf documentation (section 15.3), 
"--disable-feature is equivalent to --enable-feature=no"

Best,
Tomas

On 8/21/19 2:40 PM, Michael Chirico wrote:
> There's a bit of confusion about how to disable long double support in
an R
> build.
>
> I see --disable-long-double scattered about, e.g.
>
>     - R-exts:
>    
https://cran.r-project.org/doc/manuals/r-release/R-exts.html#Writing-portable-packages
>     - R-admin:
>     https://cran.r-project.org/doc/manuals/r-release/R-admin.html#Solaris
>     - CRAN noLD check description:
>     https://www.stats.ox.ac.uk/pub/bdr/noLD/README.txt
>     - ?capabilities:
>    
https://stat.ethz.ch/R-manual/R-devel/library/base/html/capabilities.html
>
> However, it's *missing* from ./config (cd r-source && grep
> "disable-long-double" configure). Instead there appears to be
some code
> built around enable-long-double:
>
> ./configure:1808:  --enable-long-double    use long double type [yes]
>
> ./configure:24723:# Check whether --enable-long-double was given.
>
> I see the option apparently introduced here in 2012 & the ambiguity is
> immediate -- the commit mentions disable-long-double but builds
> enable-long-double.
>
>
https://github.com/wch/r-source/commit/fb8e36f8be0aaf47a9c54c9effb219dae34f0e41
>
> Could someone please help to clear the confusion?
>
> Thanks
> Michael Chirico
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel


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