[Rd] ScalarLogical and setAttrib
Hervé Pagès
hpages at fredhutch.org
Sat Nov 1 11:50:29 CET 2014
Hi,
The problem is better illustrated with:
library(inline)
test2 <- cfunction(body = '
SEXP success = PROTECT(ScalarLogical(0));
setAttrib(success, install("foo"), mkString("bar"));
UNPROTECT(1);
return success;
')
test3 <- cfunction(body = '
SEXP success = PROTECT(ScalarLogical(0));
LOGICAL(success)[0] = 1;
UNPROTECT(1);
return success;
')
Then:
> test2()
[1] FALSE
attr(,"foo")
[1] "bar"
> test3()
[1] TRUE
attr(,"foo")
[1] "bar"
Looks like someone assumed that the SEXP returned by ScalarLogical()
would never be touched before being returned to R (which is probably
true 99% of the time but not 100%).
Cheers,
H.
On 10/31/2014 03:58 PM, Jeroen Ooms wrote:
> Is it expected that attributes set on a LGLSXP created by
> ScalarLogical will apply to all future objects created by
> ScalarLogical as well? For example: the 'test1' function below returns
> FALSE and 'test2' returns FALSE with an attribute:
>
> library(inline)
> test1 <- cfunction(body = 'return ScalarLogical(0);')
> test2 <- cfunction(body = '
> SEXP success = PROTECT(ScalarLogical(0));
> setAttrib(success, install("foo"), mkString("bar"));
> UNPROTECT(1);
> return success;
> ')
>
> However after running test2(), then test1() will also return the attribute:
>
> > test1()
> [1] FALSE
> > test2()
> [1] FALSE
> attr(,"foo")
> [1] "bar"
> > test1()
> [1] FALSE
> attr(,"foo")
> [1] "bar"
>
> It seems like ScalarLogical returns a singleton object, which is not
> the case for ScalarInteger or ScalarReal. I am currently working
> around this using duplicate(ScalarLogical(0)), but was quite surprised
> by this behavior of ScalarLogical.
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
--
Hervé Pagès
Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024
E-mail: hpages at fredhutch.org
Phone: (206) 667-5791
Fax: (206) 667-1319
More information about the R-devel
mailing list