[Rcpp-devel] convert to unsigned char* variable

[Romain Francois]

Hi, 

that's not going to fly. 

A CharacterVector holds strings of arbitrary lengths, well technically it holds other R objects (SEXP) that hold pointers to strings. 

A RawVector holds unsigned char. 

Can you add some meat to your example, e.g. what you'd expect to go in, etc ... 

Romain

> Le 20 oct. 2014 à 21:17, Gustaf Granath <gustaf.granath at gmail.com> a écrit :
> 
> 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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