删除c++函数环境中的输入R对象

I have an Rcpp function inside an R function. The R function produces some object (say a large list) and feeds it to the Rcpp function. Inside the Rcpp function, I process the R object, load the results to a number of C++ classes. Now the R object becomes useless. I want to wipe out the R object to make a memory-sufficient environment for the main algorithms.I have an Rcpp function inside an R function. T