Is the following expected behavior?
> mkext <- inline::cfunction(language="C", body='return
R_MakeExternalPtr(NULL, install("tag"), R_NilValue);')
> x <- mkext()
> y <- x
> attr(y, "foo") <- "bar"
> attributes(x)
$foo
[1] "bar"
I would expect that modifying y's attributes should not affect x.
[Tested on R version 3.3.3 x86_64-apple-darwin16.4.0 (64-bit)]
Thanks,
Patrick
potential bug in attribute handling for externalptr
3 messages · Patrick Perry, Jeroen Ooms, Lionel Henry
On Fri, Apr 14, 2017 at 11:27 PM, Patrick Perry <pperry at stern.nyu.edu> wrote:
Is the following expected behavior? I would expect that modifying y's attributes should not affect x.
Yes this is expected. Environments and external-ptr objects are never copied on assignment, hence in your example 'x' and 'y' are the same object. See e.g. ?reg.finalizer or section 5.13 of "writing r extensions" on external pointers and weak references.
This is expected behaviour, pointers are an uncopyable type, just like environments: env <- new.env() env #> <environment: 0x7fb6d4822e30> structure(env, foo = "bar") env #> <environment: 0x7fb6d4822e30> #> attr(,"foo") #> [1] "bar" On Fri, Apr 14, 2017 at 11:27 PM, Patrick Perry <pperry at stern.nyu.edu> wrote:
Is the following expected behavior?
mkext <- inline::cfunction(language="C", body='return
R_MakeExternalPtr(NULL, install("tag"), R_NilValue);')
x <- mkext() y <- x attr(y, "foo") <- "bar" attributes(x)
$foo [1] "bar" I would expect that modifying y's attributes should not affect x. [Tested on R version 3.3.3 x86_64-apple-darwin16.4.0 (64-bit)] Thanks, Patrick
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