public int ReadInterpolationProblem(string filename, out Expr[] cnsts, out uint[] parents, out string error, out Expr[] theory)
{
uint num = 0, num_theory = 0;
IntPtr[] n_cnsts;
IntPtr[] n_theory;
IntPtr n_err_str;
int r = Native.Z3_read_interpolation_problem(nCtx, ref num, out n_cnsts, out parents, filename, out n_err_str, ref num_theory, out n_theory);
error = Marshal.PtrToStringAnsi(n_err_str);
cnsts = new Expr[num];
parents = new uint[num];
theory = new Expr[num_theory];
for (int i = 0; i < num; i++)
cnsts[i] = Expr.Create(this, n_cnsts[i]);
for (int i = 0; i < num_theory; i++)
theory[i] = Expr.Create(this, n_theory[i]);
return r;
}