I have installed Rcpp, RcppParallel and I was testing simple function, written in .cpp file.

#include <RcppParallel.h>
#include <Rcpp.h>
#include <vector>

using namespace RcppParallel;
using namespace Rcpp;

struct Sum : public Worker {
  // Source vector
  const std::vector<int> &input;

  // Accumulated value
  int value;

  // Constructor
  Sum(const std::vector<int> &input) : input(input), value(0) {}

  // Split constructor
  Sum(const Sum &sum, Split) : input(sum.input), value(0) {}

  // Accumulate values in the given range
  void operator()(std::size_t begin, std::size_t end) {
    value += std::accumulate(input.begin() + begin, input.begin() + end, 0);
  }

  // Join the accumulated values
  void join(const Sum &rhs) {
    value += rhs.value;
  }
};

// [[Rcpp::export]]
int parallelSum(const std::vector<int> &x) {
  Sum sum(x);

  // Call parallelReduce to start the work
  parallelReduce(0, x.size(), sum);

  return sum.value;
}

then:

sourceCpp("UntitledCPP.cpp")

It gave me:

sourceCpp("UntitledCPP.cpp")
using C++ compiler: 'G__~1.EXE (GCC) 13.2.0'
g++ -std=gnu++17  -I"C:/PROGRA~1/R/R-44~1.1/include" -DNDEBUG   -I"C:/Users/callimae/AppData/Local/R/win-library/4.3/Rcpp/include" -I"C:/Users/callimae/Documents/Projects/NewEM_conjugate_base"   -I"C:/rtools44/x86_64-w64-mingw32.static.posix/include"     -O2 -Wall  -mfpmath=sse -msse2 -mstackrealign  -c UntitledCPP.cpp -o UntitledCPP.o
UntitledCPP.cpp:1:10: fatal error: RcppParallel.h: No such file or directory
    1 | #include <RcppParallel.h>
      |          ^~~~~~~~~~~~~~~~
compilation terminated.
make: *** [C:/PROGRA~1/R/R-44~1.1/etc/x64/Makeconf:296: UntitledCPP.o] Error 1
Error in sourceCpp("UntitledCPP.cpp") : 
  Error 1 occurred building shared library.

While i specified full path to RcppParallel, it asked about tinythread instead.

I have new version of R and Rtools. My session info:

sessionInfo()
R version 4.4.1 (2024-06-14 ucrt)
Platform: x86_64-w64-mingw32/x64
Running under: Windows 11 x64 (build 22631)

Matrix products: default


locale:
[1] LC_COLLATE=Polish_Poland.utf8  LC_CTYPE=Polish_Poland.utf8    LC_MONETARY=Polish_Poland.utf8 LC_NUMERIC=C                  
[5] LC_TIME=Polish_Poland.utf8    

time zone: Europe/Warsaw
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] RcppArmadillo_14.0.0-1 RcppParallel_5.1.8     Rcpp_1.0.12           

loaded via a namespace (and not attached):
 [1] compiler_4.4.1    magrittr_2.0.3    cli_3.6.3         tools_4.4.1       fs_1.6.4          glue_1.7.0        rstudioapi_0.16.0 vctrs_0.6.5      
 [9] usethis_2.2.3     lifecycle_1.0.4   rlang_1.1.4       purrr_1.0.2      

I have reinstalled all rcpp packages as well.
Do you have any ideas?

Kind regards,

Mateusz