Warning message In if (nchar(CXX) > 0) return(TRUE) appears for all Stan models

We are using a virtual desktop infrastructure (VDI) at company. I just installed Rstan on my VDI, and tried some tests on the installation. The version of R is 3.5.0, Rstan is 2.17.3, Rtools is 3.3. All the installations are done on the server that I don’t have privilege of administrator. It seems that the installation didn’t add path of rtools to the system path environment. system('g++ -v') returns nothing, no error or any message. I tried the 8school example, and a simple Bernoulli example as below:

  // test.stan
data {
  int<lower = 0> N;
  int<lower = 0, upper = 1> y[N];
parameters {
  real<lower = 0, upper = 1> p;

model {
  p ~ beta(1, 2);
  y ~ bernoulli(p);

Both models compiled with no error, but there is a warning message always appears:

" Warning message:
In if (nchar(CXX) > 0) return(TRUE) :
the condition has length > 1 and only the first element will be used"

rstan:::get_CXX() returns “C:/FAST/RTools/3.3/mingw_/bin/g++”.

I never went into such issue with my personal laptop.

Do you know what might be the cause for this warning message?


This should be
(or perhaps 32 instead of 64 if it is a 32 bit environment). It seems as if the WIN environmental variable is not being set somehow.