similar to: Memory Protection & calling C-fun from C

For using R's .Call interface to C functions, all the examples I've seen have the C function return type SEXP. Why? What does R actually do with this return type? What happens if I *don't* return a SEXP? Reason I ask, is I've written some R code which allocates two long lists, and then calls a C function with .Call. My C code writes to those two pre-allocated lists, thus, I

Hi, the following example aiming at a class containing a logical slot segfaults under R-1.9.0 when `gctorture(on = TRUE)' is used: Code code (dummy.c): #include <Rdefines.h> SEXP foo() { SEXP ans; PROTECT(ans = NEW_OBJECT(MAKE_CLASS("test"))); SET_SLOT(ans, install("lgl"), allocVector(LGLSXP, 1)); LOGICAL(GET_SLOT(ans,

Dear R developers, I've just encountered one "feature" of R-C extensions. If it is known, I would be thankful for any hints why it works this way (I found the way around, which is also mentioned here, but maybe it is not the best one). If it is however unknown, it might be considered for a "wish list". Consider a simple "aka" C function (the original

Hello, Suppose I have the function SEXP foo(){ SEXP s; PROTECT(s=allocVector(...)) .... UNPROTECT(1); return(s) } y=foo() // foo is a recusrive call Q: Am i correct in understanding that one does not need to write PROTECT(y=foo()) ?(and a corresponding unprotect later on) since it is the object that is protected , SEXP is an alias for SEXPREC* and allocVector probably does some memory

Hi, I'm troubleshooting some native code on Windows that very occationally (and semi-randomly) crashes R. Already looked at "everything", I just want to double check that it is safe to UNPROTECT() allocated variables as soon as they are assigned to, say, a PROTECTed list. >From (R v2.3.0) Section 5.7.1 "Handling the effects of garbage collection" in "Writing R

there is my code,  expect return value  is a data frame but R say it is list: SEXP Julia_R_MD_NA_DataFrame(jl_value_t* Var) {  SEXP ans,names,rownames;  char evalcmd[4096];  int i;  const char* dfname="DataFrameName0tmp";  jl_set_global(jl_main_module, jl_symbol(dfname), (jl_value_t*)Var);  //Get Frame cols   sprintf(evalcmd,"size(%s,2)",dfname);  jl_value_t*

Dear list, I am trying to implement a publish-subscribe mechanism in for an embedded R interpreter. But somehow my registered closures seem to get collected by the GC, even though I have protected them. I have reducted my code to the following sample. Sorry if it is a little verbose. The first couple of call of calls still work, but at some point one of the callbacks (callback1 in my

Consider the C (or C++) code called from the .Call interface: SEXP foo() { SEXP *p = PROTECT(allocVector(REALSXP, 10)); ... UNPROTECT(1); return p; } Why is there no danger that the allocated memory will be garbage collected after the UNPROTECT, but before the return of p? I have used code like this for some time and have never had a problem, but I'm not sure if/why it is guaranteed

Dear R .Call() insiders, Can someone enlighten me how to properly finalize external pointers in C code (R-2.5.1 win)? What is the relation between R_ClearExternalPtr and the finalizer set in R_RegisterCFinalizer? I succeeded registering a finalizer that works when an R object containing an external pointer is garbage collected. However, I have some difficulties figuring out how to do that in an

Hi, I'm wondering if this code from the "Writing R Extensions" manual is really safe: SEXP mkans(double x) { SEXP ans; PROTECT(ans = allocVector(REALSXP, 1)); REAL(ans)[0] = x; UNPROTECT(1); return ans; } double feval(double x, SEXP f, SEXP rho) { defineVar(install("x"), mkans(x), rho);

Hi, Trying to decrease the size of a SEXP variable without reassigning values individually in a loop. So far, I've tried using Realloc, as the follow source demonstrates: SEXP dothis() { SEXP Rblah; PROTECT(Rblah = NEW_INTEGER(6)); int* blah = INTEGER(Rblah); blah[0] = 1; blah[1] = 2; blah[2] = 3; Realloc(Rblah, 3, INTEGER); UNPROTECT(1); return(Rblah); } According to the

I want to write an R function using R's C interface that takes a 2-column matrix of increasing, non-overlapping integer intervals and returns a list with those intervals plus some added intervals, such that there are no gaps. For example, it should take the matrix rbind(c(5L, 6L), c(7L, 10L), c(20L, 30L)) and return list(c(5L, 6L), c(7L, 10L), c(11L, 19L), c(20L, 30L)). Because the output is

Dear R-dev, I would like to accelerate my R computation by using parallel OpenMP compilers (e.g from Pathscale) on a 2-processor AMD server and I would like to know whether R is a tread safe library. The main kernel of the OpenMP parallelization is a C SEXP function that performs the computational routine in parallel with: ******************* SEXP example(SEXP list, SEXP expr, SEXP rho) {

Hi , I am trying to create a dataframe in C and sebd it back to R. Can anyone point me to the part of the source code where it is doing , let me explain the problem I am having . -------------------------------------------------------------------- My simple implementation is like this SEXP formDF() { SEXP dfm ,df , dfint , dfStr,lsnm; char *ab[3] =

Hi List, I'd imagine this is a question that has been answered before, but I can't seem to track it down, sorry for the duplication if it has. I am writing an interface for a C library and want to return an S4 class from the 'constructing' method. One of the slots of the argument to be returned will be filled with one of the arguments passed to the function. My question is about

Dear R experts! I want to evaluate expressions from within C code. For instance, I want this code: /* ============ -- C code -- ============== */ #include <R.h> #include <Rinternals.h> SEXP foo(SEXP expr, SEXP rho) { SEXP x; PROTECT(x = allocVector(REALSXP, 1)); REAL(x)[0] = 1; UNPROTECT(1); return

Hi, I work with SEXP C code and with xts and quantmod packages. I try to touch how xts internal works. So we have R session and: > ls() character(0) > getSymbols('AAPL') # quantmod package [1] "AAPL" > ls() [1] "AAPL" > str(AAPL) An ?xts? object from 2007-01-03 to 2010-09-09 containing: Data: num [1:929, 1:6] 86.3 84 85.8 86 86.5 ... - attr(*,

Hello, Just a quick question on best practise. I am converting quite a bit of legacy C code into R packages and have the following situation: (1) Legacy object with a double* array in, all over code so don't want to change any more than I have to. (2) Do something like: SEXP arrayToPassToR; PROTECT( arrayToPassToR = allocVector( REALSXP, n ) ); for(i=0; i < n; i++) {

Hi, I am looking for C/C++ codes for computing generalized inverse of a matrix. Can anyone help me in this regard? Thanks, Mahbub.

Hi all I recently started to write a matrix exponentiation operator for R (by adding a new operator definition to names.c, and adding the following code to arrays.c). It is not finished yet, but I would like to solicit some comments, as there are a few areas of R's internals that I am still feeling my way around. Firstly: 1) Would there be interest in adding a new operator %^% that performs