Kasper Daniel Hansen
khansen at stat.Berkeley.EDU
Tue May 23 08:39:31 CEST 2006
I have a few simple questions about the usage of PROTECT, more
specifically how careful one needs to be. Simple yes/no answers are
Most of the uses I have seen do protection when memory is allocated.
But what if one just want to assign a value of another function to a
variable. Say eg. that foo is a function that returns a SEXP. Would
the following code be fine?
PROTECT(bar = foo());
Also, basically in one use case I would want to return the value of
foo immediately, but I need to do some cleaning up first, which has
nothing to do with R (more specifically, I need to close various
files). Would I then need to protect foo, as in
bar = foo();
"close the file in C++"
Finally, I am also assigning values to the components of a list.
Would the following be ok
PROTECT(bar = NEW_LIST(2));
SET_VECTOR_ELT(bar, 0, ScalarInteger(test());
(where test is a function returning int, which again has nothing to
do with R - it interfaces to an extern library), or do I need to
hedge myself against garbage collection in the SET_VECTOR_ELT macro?
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