# Windows/Rstan: compiler flags not being picked up?

**URL:** <https://discourse.mc-stan.org/t/windows-rstan-compiler-flags-not-being-picked-up/10010>\
**Category:** RStan\
**Created:** [August 1, 2019, 2:28am UTC](https://discourse.mc-stan.org/t/windows-rstan-compiler-flags-not-being-picked-up/10010 "2019-08-01T02:28:15Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![JulianK](https://avatars.discourse-cdn.com/v4/letter/j/779978/32.png) [@JulianK](https://discourse.mc-stan.org/u/JulianK)\
**Post date:** [August 1, 2019, 2:28am UTC](https://discourse.mc-stan.org/t/windows-rstan-compiler-flags-not-being-picked-up/10010/1 "2019-08-01T02:28:15Z")

</div>

Hello,

I am unsure whether my Makevars settings are being picked up by Stan.

My Makevars settings are below but the DSO signature in the stanFit object is different:

```
.. .. ..@ dso :Formal class 'cxxdso' [package "rstan"] with 7 slots
  .. .. .. .. ..@ sig :List of 1
  .. .. .. .. .. ..$ file715860c76949: chr(0) 
  .. .. .. .. ..@ dso_saved : logi TRUE
  .. .. .. .. ..@ dso_filename: chr "file715860c76949"
  .. .. .. .. ..@ modulename : chr "stan_fit4model71585464310f_GP"
  .. .. .. .. ..@ system : chr "x86_64, mingw32"
  .. .. .. .. ..@ cxxflags : chr "CXXFLAGS = -O2 -Wall $(DEBUGFLAG) -mtune=core2"
  .. .. .. .. ..@ .CXXDSOMISC :<environment: 0x0000017395d3c6f8> 

```

Is this the correct behaviour? Should I not be seeing the -O3?

- Operating System: Windows
- RStan Version: 2.19.2

**Output of `writeLines(readLines(file.path(Sys.getenv("HOME"), ".R/Makevars")))`:**

```
CXX14FLAGS=-O3
CXX14 = g++ -m$(WIN) -std=c++1y
CXX11FLAGS=-O3
STAN_OPENCL=true
OPENCL_PLATFORM_ID=1
OPENCL_DEVICE_ID=0
CC = g++
LDFLAGS_OPENCL= -L"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v10.1\lib\x64" -lOpenCL

```

(I have the same settings in `Makevars.win`)

**Output of `devtools::session_info("rstan")`**

```
> devtools::session_info("rstan")
- Session info ----------------------------------------------------------------------------------------------------------------------------

- Packages --------------------------------------------------------------------------------------------------------------------------------
 ! package * version date lib source        
   assertthat 0.2.1 2019-03-21 [1] CRAN (R 3.5.3)
   backports 1.1.4 2019-04-10 [1] CRAN (R 3.5.3)
   BH 1.69.0-1 2019-01-07 [1] CRAN (R 3.5.2)
   callr 3.3.1 2019-07-18 [1] CRAN (R 3.5.3)
   checkmate 1.9.4 2019-07-04 [1] CRAN (R 3.5.3)
   cli 1.1.0 2019-03-19 [1] CRAN (R 3.5.3)
   colorspace 1.4-1 2019-03-18 [1] CRAN (R 3.5.3)
   crayon 1.3.4 2017-09-16 [1] CRAN (R 3.5.3)
   desc 1.2.0 2018-05-01 [1] CRAN (R 3.5.3)
   digest 0.6.20 2019-07-04 [1] CRAN (R 3.5.3)
   ellipsis 0.2.0.1 2019-07-02 [1] CRAN (R 3.5.3)
   fansi 0.4.0 2018-10-05 [1] CRAN (R 3.5.3)
   ggplot2 * 3.2.0 2019-06-16 [1] CRAN (R 3.5.3)
   glue 1.3.1 2019-03-12 [1] CRAN (R 3.5.3)
   gridExtra 2.3 2017-09-09 [1] CRAN (R 3.5.3)
   gtable 0.3.0 2019-03-25 [1] CRAN (R 3.5.3)
   inline 0.3.15 2018-05-18 [1] CRAN (R 3.5.3)
   labeling 0.3 2014-08-23 [1] CRAN (R 3.5.2)
   lattice 0.20-35 2017-03-25 [?] CRAN (R 3.5.1)
   lazyeval 0.2.2 2019-03-15 [1] CRAN (R 3.5.3)
   loo 2.1.0 2019-03-13 [1] CRAN (R 3.5.3)
   magrittr 1.5 2014-11-22 [1] CRAN (R 3.5.3)
   MASS 7.3-50 2018-04-30 [?] CRAN (R 3.5.1)
   Matrix 1.2-14 2018-04-13 [?] CRAN (R 3.5.1)
   matrixStats 0.54.0 2018-07-23 [1] CRAN (R 3.5.3)
   mgcv 1.8-24 2018-06-23 [?] CRAN (R 3.5.1)
   munsell 0.5.0 2018-06-12 [1] CRAN (R 3.5.3)
   nlme 3.1-137 2018-04-07 [?] CRAN (R 3.5.1)
   pillar 1.4.2 2019-06-29 [1] CRAN (R 3.5.3)
   pkgbuild 1.0.3 2019-03-20 [1] CRAN (R 3.5.3)
   pkgconfig 2.0.2 2018-08-16 [1] CRAN (R 3.5.3)
   plyr 1.8.4 2016-06-08 [1] CRAN (R 3.5.3)
   prettyunits 1.0.2 2015-07-13 [1] CRAN (R 3.5.3)
   processx 3.4.1 2019-07-18 [1] CRAN (R 3.5.3)
   ps 1.3.0 2018-12-21 [1] CRAN (R 3.5.3)
 P R6 2.2.2 2017-06-17 [3] CRAN (R 3.5.0)
   RColorBrewer 1.1-2 2014-12-07 [1] CRAN (R 3.5.2)
   Rcpp 1.0.2 2019-07-25 [1] CRAN (R 3.5.3)
   RcppEigen 0.3.3.5.0 2018-11-24 [1] CRAN (R 3.5.3)
   reshape2 1.4.3 2017-12-11 [1] CRAN (R 3.5.3)
   rlang 0.4.0 2019-06-25 [1] CRAN (R 3.5.3)
   rprojroot 1.3-2 2018-01-03 [1] CRAN (R 3.5.3)
   rstan * 2.19.2 2019-07-09 [1] CRAN (R 3.5.3)
   scales 1.0.0 2018-08-09 [1] CRAN (R 3.5.3)
   StanHeaders * 2.18.1-10 2019-06-14 [1] CRAN (R 3.5.3)
   stringi 1.4.3 2019-03-12 [1] CRAN (R 3.5.3)
   stringr 1.4.0 2019-02-10 [1] CRAN (R 3.5.3)
   tibble 2.1.3 2019-06-06 [1] CRAN (R 3.5.3)
   utf8 1.1.4 2018-05-24 [1] CRAN (R 3.5.3)
   vctrs 0.2.0 2019-07-05 [1] CRAN (R 3.5.3)
   viridisLite 0.3.0 2018-02-01 [1] CRAN (R 3.5.3)
   withr 2.1.2 2018-03-15 [1] CRAN (R 3.5.3)
   zeallot 0.1.0 2018-01-28 [1] CRAN (R 3.5.3)

```

Thanks!

---

<div class="post-metadata">

**Author:** ![bgoodri](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/bgoodri/32/4451_2.png) [@bgoodri](https://discourse.mc-stan.org/u/bgoodri)\
**Post date:** [August 1, 2019, 3:54am UTC](https://discourse.mc-stan.org/t/windows-rstan-compiler-flags-not-being-picked-up/10010/2 "2019-08-01T03:54:19Z")

</div>

I wouldn’t worry about what it says in `dso` because we aren’t doing anything with the `cxxflags`. Look at the output when you specify the `verbose = TRUE` argument to `stan_model` or `stan` if you have any doubt as to what flags were used.