[Rd] Please avoid direct use of NAMED and SET_NAMED macros

[luke-tierney at uiowa.edu]

On Sat, 2 Sep 2017, Radford Neal wrote:

>> To allow for future changes in the way the need for duplication is
>> detected in R internal C code, package C code should avoid direct
>> use of NAMED,and SET_NAMED, or assumptions on the maximal value
>> of NAMED. Use the macros MAYBE_REFERENCED, MAYBE_SHARED, and
>> MARK_NOT_MUTABLE instead. These currently correspond to
>>
>> MAYBE_REFERENCED(x):   NAMED(x) > 0
>> MAYBE_SHARED(x):       NAMED(x) > 1
>> MARK_NOT_MUTABLE(x):   SET_NAMED(c, NAMEDMAX)
>>
>> Best,
>>
>> luke
>
>
> Checking https://cran.r-project.org/doc/manuals/r-release/R-exts.html
> shows that currently there is no mention of these macros in the
> documentation for package writers.  Of course, the explanation of
> NAMED there also does not adequtely describe what it is supposed to
> mean, which may explain why it's often not used correctly.

As of yesterday they are mentioned in the R-devel version of this
manual, which will make it to the web in due course.

> Before embarking on a major change to the C API, I'd suggest that you
> produce clear and complete documention on the new scheme.
>
>    Radford Neal
>

-- 
Luke Tierney
Ralph E. Wareham Professor of Mathematical Sciences
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