Function Rcpp_protect

inst/include/Rcpp/protection/Shield.h:23–26

namespace Rcpp{

    inline SEXP Rcpp_protect(SEXP x){
        if( x != R_NilValue ) PROTECT(x) ;
        return x ;
    }

    inline void Rcpp_unprotect(int i){
        // Prefer this function over UNPROTECT() in Rcpp so that all