[Rd] creating environments in package's C code

Jeff Horner jeff.horner at vanderbilt.edu
Thu Oct 1 18:07:33 CEST 2009

Martin Becker wrote:
> Dear developers,
> is it possible to create environments in C code of packages?
> Simply using
>  SEXP env;
>  PROTECT (env  = allocSExp(ENVSXP));
> and assigning the enclosing environment with SET_ENCLOS seems to be 
> insufficient.
> Best wishes,

Here's a function I use in rapache to create one:

static SEXP NewEnv(SEXP enclos){
     SEXP env;
     PROTECT(env = allocSExp(ENVSXP));

     SET_FRAME(env, R_NilValue);
     SET_ENCLOS(env, (enclos)? enclos: R_GlobalEnv);
     SET_HASHTAB(env, R_NilValue);
     SET_ATTRIB(env, R_NilValue);


     return env;

and an example that creates a new environment and then assigns a 
variable named OK an integer vector length 1 with value 0:

SEXP env = NewEnv(R_GlobalEnv);



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