Build error in array.flags().c_contiguous.

[Shin-ichi-Takayama]

Hi all, I'm looking for some help.
I have cmake built the following code.

#include <pybind11/pybind11.h>
#include <pybind11/numpy.h>

namespace py = pybind11;

float my_cpp_function(float *data, int size) {
  float sum = 0;
  for (int i = 0; i < size; i++) {
    // do something with the data
    sum += data[i];
  }
  return sum;
}

// Wrap the C++ function with pybind11
// Use NumPy array as input and output
float my_py_function(py::array_t<float> input_array) {
    // Check if the input array is contiguous
    if (!input_array.flags().c_contiguous) {
        throw std::runtime_error("Input array must be contiguous");
    }

    // Get a pointer to the underlying data
    float *data = static_cast<float *>(input_array.request().ptr);
    // Get the size of the input array
    int size = input_array.size();
    // Call the C++ function
    float out = my_cpp_function(data, size);
    // Return the modified array
    return out;
}

// Define the module and the bindings
PYBIND11_MODULE(example2, m) {
    m.def("my_function", &my_py_function, "A function that takes a NumPy array as input and modifies it in-place");
}

I got the following build error.

[ 33%] Building CXX object CMakeFiles/example2.dir/example2.cpp.o
/root/example2.cpp:22:29: error: member reference base type 'int' is not a structure or union
    if (!input_array.flags().c_contiguous) {
         ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
1 error generated.
make[2]: *** [CMakeFiles/example2.dir/build.make:63: CMakeFiles/example2.dir/example2.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:76: CMakeFiles/example2.dir/all] Error 2
make: *** [Makefile:84: all] Error 2

How can I deal with this?

Ubuntu version: 20.04
pytyhon version: 3.8.10
cmake version: 3.16.3
pybind version: 2.4.3

Best regards.