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.
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--
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: [email protected]
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