[Rcpp-devel] convert to unsigned char* variable

Gustaf Granath gustaf.granath at gmail.com
Mon Oct 20 21:17:10 CEST 2014


Hi
Im trying to use some C++ functions in R. However, these functions are 
build around unsigned char* variables (1D array). I have for example a 
large matrix in R that represents black (e.g. 1-bit image, 0 and 1s). I 
cant find a solution to convert a character vector into unsigned char* 
within Rcpp. Im new to Rcpp and C++ so I might have missed something 
obvious here. Please direct me to resources on this topic (google did 
not help much).

A start:

SEXP test(SEXP cM){
   CharacterVector Vc(cM);
   int n = Vr.size();
   RawVector x(n); //is this the same as unsigned char* ?
                             //I tried to fill it with char*(Mr) but I 
didnt succeed
}

Thanks,

Gustaf

-- 
Gustaf Granath (PhD)
Post doc
McMaster University
School of Geography & Earth Sciences



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