Linker errors for OpenBlas (+Armadillo)

Question

I was previously using Armadillo with blas and lapack but have decided to use OpenBlas to speed up computations. I have followed the steps given in this link and compiled OpenBlas in MinGW to generate libopenblas.dll and libopenblas.dll.a. Now I have tried to use these in an example application in VS 2012 and found linker errors related to OpenBlas. What am I doing wrong?

The example is given below:

#include <iostream>
#include <armadillo>

using namespace std;
using namespace arma;


int
main(int argc, char** argv)
{
  cout << "Armadillo version: " << arma_version::as_string() << endl;

  mat A(2,3);  // directly specify the matrix size (elements are uninitialised)

  cout << "A.n_rows: " << A.n_rows << endl;  // .n_rows and .n_cols are read only
  cout << "A.n_cols: " << A.n_cols << endl;

  A(1,2) = 456.0;  // directly access an element (indexing starts at 0)
  A.print("A:");


  A = 5.0;         // scalars are treated as a 1x1 matrix
  A.print("A:");


  A.set_size(4,5); // change the size (data is not preserved)

  A.fill(5.0);     // set all elements to a particular value
  A.print("A:");

  // endr indicates "end of row"
  A << 0.165300 << 0.454037 << 0.995795 << 0.124098 << 0.047084 << endr
    << 0.688782 << 0.036549 << 0.552848 << 0.937664 << 0.866401 << endr
    << 0.348740 << 0.479388 << 0.506228 << 0.145673 << 0.491547 << endr
    << 0.148678 << 0.682258 << 0.571154 << 0.874724 << 0.444632 << endr
    << 0.245726 << 0.595218 << 0.409327 << 0.367827 << 0.385736 << endr;

   A.print("A:");

  // determinant
  cout << "det(A): " << det(A) << endl;

  // inverse
  cout << "inv(A): " << endl << inv(A) << endl;

  // save matrix as a file
  A.save("A.txt", raw_ascii);

  // load from file
  mat B;
  B.load("A.txt");

  // submatrices
  cout << "B( span(0,2), span(3,4) ):" << endl << B( span(0,2), span(3,4) ) << endl;

  cout << "B.row(0): " << endl << B.row(0) << endl;

  cout << "B.col(1): " << endl << B.col(1) << endl;

 // transpose
  cout << "B.t(): " << endl << B.t() << endl;

  // maximum from each column (traverse along rows)
  cout << "max(B): " << endl << max(B) << endl;

  // maximum from each row (traverse along columns)
  cout << "max(B,1): " << endl << max(B,1) << endl;

  // maximum value in B
  cout << "max(max(B)) = " << max(max(B)) << endl;

  // sum of each column (traverse along rows)
  cout << "sum(B): " << endl << sum(B) << endl;

  // sum of each row (traverse along columns)
  cout << "sum(B,1) =" << endl << sum(B,1) << endl;

  // sum of all elements
  cout << "accu(B): " << accu(B) << endl;

  // trace = sum along diagonal
  cout << "trace(B): " << trace(B) << endl;

  // generate the identity matrix
  mat C = eye<mat>(4,4);

  // random matrix with values uniformly distributed in the [0,1] interval
  mat D = randu<mat>(4,4);
  D.print("D:");

  // row vectors are treated like a matrix with one row
  rowvec r;
  r << 0.59119 << 0.77321 << 0.60275 << 0.35887 << 0.51683;
  r.print("r:");

  // column vectors are treated like a matrix with one column
  colvec q;
  q << 0.14333 << 0.59478 << 0.14481 << 0.58558 << 0.60809;
  q.print("q:");

  // dot or inner product
  cout << "as_scalar(r*q): " << as_scalar(r*q) << endl;

  // outer product
  cout << "q*r: " << endl << q*r << endl;

  // multiply-and-accumulate operation (no temporary matrices are created)
  cout << "accu(A % B) = " << accu(A % B) << endl;

  // example of a compound operation
  B += 2.0 * A.t();
  B.print("B:");

  // imat specifies an integer matrix
  imat AA;
  imat BB;

  AA << 1 << 2 << 3 << endr << 4 << 5 << 6 << endr << 7 << 8 << 9;
  BB << 3 << 2 << 1 << endr << 6 << 5 << 4 << endr << 9 << 8 << 7;

  // comparison of matrices (element-wise); output of a relational operator is a umat
  umat ZZ = (AA >= BB);
  ZZ.print("ZZ:");

  // cubes ("3D matrices")
  cube Q( B.n_rows, B.n_cols, 2 );

  Q.slice(0) = B;
  Q.slice(1) = 2.0 * B;

  Q.print("Q:");

  // 2D field of arbitrary length row vectors (fields can also store abitrary objects, eg. instances of std::string)
  field<rowvec> xyz(3,2);

  xyz(0,0) = randu(1,2);
  xyz(1,0) = randu(1,3);
  xyz(2,0) = randu(1,4);
  xyz(0,1) = randu(1,5);
  xyz(1,1) = randu(1,6);
  xyz(2,1) = randu(1,7);

  cout << "xyz:" << endl;
  cout << xyz << endl;

  return 0;
 }

The linker errors are:

 1>example1.obj : error LNK2019: unresolved external symbol ddot_ referenced in function "public: static void __cdecl arma::syrk_vec<1,1,0>::apply<double,class arma::Col<double> >(class arma::Mat<double> &,class arma::Col<double> const &,double,double)" (??$apply@NV?$Col@N@arma@@@?$syrk_vec@$00$00$0A@@arma@@SAXAEAV?$Mat@N@1@AEBV?$Col@N@1@NN@Z)
 1>example1.obj : error LNK2019: unresolved external symbol dgemv_ referenced in function "public: static void __cdecl arma::gemv<1,1,0>::apply_blas_type<double,class arma::Col<double> >(double *,class arma::Col<double> const &,double const *,double,double)" (??$apply_blas_type@NV?$Col@N@arma@@@?$gemv@$00$00$0A@@arma@@SAXPEANAEBV?$Col@N@1@PEBNNN@Z)
 1>example1.obj : error LNK2019: unresolved external symbol dgemm_ referenced in function "public: static void __cdecl arma::gemm<1,1,1,0>::apply_blas_type<double,class arma::Col<double>,class arma::Row<double> >(class arma::Mat<double> &,class arma::Col<double> const &,class arma::Row<double> const &,double,double)" (??$apply_blas_type@NV?$Col@N@arma@@V?$Row@N@2@@?$gemm@$00$00$00$0A@@arma@@SAXAEAV?$Mat@N@1@AEBV?$Col@N@1@AEBV?$Row@N@1@NN@Z)
 1>example1.obj : error LNK2019: unresolved external symbol dsyrk_ referenced in function "public: static void __cdecl arma::syrk<1,1,0>::apply_blas_type<double,class arma::Col<double> >(class arma::Mat<double> &,class arma::Col<double> const &,double,double)" (??$apply_blas_type@NV?$Col@N@arma@@@?$syrk@$00$00$0A@@arma@@SAXAEAV?$Mat@N@1@AEBV?$Col@N@1@NN@Z)
 1>D:\iUH\Research\armadillo-5.200.1\examples\x64\Debug\example1_win64.exe : fatal error LNK1120: 4 unresolved externals