c - Template function to print a Thrust vector -

i'm writing matrix template class prints both file , std::cout, i.e.:

matrix<float> mymat; ... mymat.cout(...)         // print std::cout mymat.write("out.txt")  // print file 

both share common underlying printing function i'm trying implement template too, since i've seen different examples use thrust::copy write data both std::cout , files.

below skeleton of i've done, is outputting garbage. point errors may have made? example, allowed pass std::cout around this?

template <typename data_t> matrix {     ...      template <typename out_t> int printto(out_t &out, ...) {         data_t *start = ..., *end = ...;         ...         thrust::copy(start, end, std::ostream_iterator<data_t>(out, " "));         ...     }      int cout(...) {         ...         printto(std::cout, ...);         ...     }      int write(char* path, ...) {         ...         std::ofstream file;         file.open(path);         printto(file, ...);         ...     } } 

edit:

• changing int printto(std::ostream &out, ...) {...} not fix problem.
• more info: read data matrix thrust::device_vector<t>, dvec, , convert data_t pointer pvec using thrust::raw_pointer_cast(&dvec[0]) (as cublas library uses raw pointers). operate on pvec , want print out.
• i've tried printing pointer of original thrust::device_vector directly (i.e. *dvec) , does work: thrust::copy((*dvec).begin(), (*dvec).begin() + n ...). why can copy using *dvec iterators , not raw pointer cast pvec?

don't use raw_pointer_cast here. fool thrust thinking you've got pointer data on host, why code isn't giving expect. have expected code crash.

to copy device_vector ostream_iterator, use thrust::copy directly:

thrust::device_vector<float> vec = ...  thrust::copy(vec.begin(), vec.end(), std::ostream_iterator<float>(std::cout, " "));