user buffer_protocol() in pybind11 for a custom class

[AAUDI]

Hi,

I have a templated class and I have a method inside this class that return a pointer of the raw buffer.

I tried to use buffer_protocol to return a numpy array directly in python side from the raw buffer.

This way works well for standard types (float, int double, string, etc ..) but I need to used it for a custom type.

template < class T>

class Array1D { 

public:
Array1D()
 {
     Init();
 }

 Array1D(const uint32_t size)
 {
     Init();
     SetSize(size);
 }

 Array1D(const  Array1D<T> &obj)
 {
     Init();
     *this = obj;
 }

 const T& operator[](uint32_t n)const
 {
     S_ASSERT((n < m_nSize));
     return m_pData[n];
 }

 T& operator[](uint32_t n)
 {
     S_ASSERT((n < m_nSize));
     return m_pData[n];
 }

 
 inline const T* GetBuffer()const
 {
     return m_pData;
 }

 inline T* GetBuffer()
 {
     return m_pData;
 }

protected: 
T*m_pData; 
uint32_t m_nSize;
uint32_t m_nCapacity;
bool     m_bDeleteBuffer; 
};

I used this code to bind what I say above :

.def_buffer([](Array1D<T> &m)->py::buffer_info {

       return py::buffer_info(
                                          m.GetBuffer(), 
                                          sizeof(T), 
                                          py::format_descriptor<T>::format(), 
                                          1, 
                                          {m.GetSize()},
                                          {sizeof(T)}
                                         );
 }

It works well when I call my module like this :

export_Array1D<S_INT8>(m, "S_INT8");
export_Array1D<float>(m, "float");

But when I tried this :

export_Array1D<MyOwnClass>(m, "MyOwnClass");
I have this error :

error: ‘format’ is not a member of ‘pybind11::format_descriptor<MyOwnClass, void>’

Do we have any way that can resolve this problem? In other words, Can we use buffer_protocol and .def_buffer() to get the numpy array from a raw buffer of a custom type ?

Thank you